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“Grain boundaries as a diffusion-limiting factor in lithium-rich NMC cathodes for high-energy lithium-ion batteries”. Abakumov AM, Li C, Boev A, Aksyonov DA, Savina AA, Abakumova TA, Van Tendeloo G, Bals S, ACS applied energy materials 4, 6777 (2021). http://doi.org/10.1021/ACSAEM.1C00872
Abstract: High-energy lithium-rich layered transition metal oxides are capable of delivering record electrochemical capacity and energy density as positive electrodes for Li-ion batteries. Their electrochemical behavior is extremely complex due to sophisticated interplay between crystal structure, electronic structure, and defect structure. Here we unravel an extra level of this complexity by revealing that the most typical representative Li1.2Ni0.13Mn0.54Co0.13O2 material, prepared by a conventional coprecipitation technique with Na2CO3 as a precipitating agent, contains abundant coherent (001) grain boundaries with a Na-enriched P2-structured block due to segregation of the residual sodium traces. The trigonal prismatic oxygen coordination of Na triggers multiple nanoscale twinning, giving rise to incoherent (104) boundaries. The cationic layers at the (001) grain boundaries are filled with transition metal cations being Mn-depleted and Co-enriched; this makes them virtually not permeable for the Li+ cations, and therefore they negatively influence the Li diffusion in and out of the spherical agglomerates. These results demonstrate that besides the mechanisms intrinsic to the crystal and electronic structure of Li-rich cathodes, their rate capability might also be depreciated by peculiar microstructural aspects. Dedicated engineering of grain boundaries opens a way for improving inherently sluggish kinetics of these materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 4
DOI: 10.1021/ACSAEM.1C00872
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“Exploring the role of graphene oxide as a co-catalyst in the CZTS photocathodes for improved photoelectrochemical properties”. Vishwakarma M, Batra Y, Hadermann J, Singh A, Ghosh A, Mehta BR, ACS applied energy materials 5, 7538 (2022). http://doi.org/10.1021/ACSAEM.2C01011
Abstract: The hydrogen evolution properties of CZTS heterostructure photocathodes are reported with graphene oxide (GO) as a co-catalyst layer coated by a drop-cast method and an Al2O3 protection layer fabricated using atomic layer deposition. In the CZTS absorber, a minor deviation from stoichiometry across the cross section of the thin film results in nanoscale growth of spurious phases, but the kesterite phase remains the dominant phase. We have investigated the band alignment parameters such as the band gap, work function, and Fermi level position that are crucial for making kesterite-based heterostructure devices. The photocurrent density in the photocathode CZTS/CdS/ZnO is found to be improved to -4.71 mAmiddotcm(-2) at -0.40 V-RHE, which is 3 times that of the pure CZTS. This enhanced photoresponse can be attributed to faster carrier separation at p-n junction regions driven by upward band bending at CZTS grain boundaries and the ZnO layer. GO as a co-catalyst over the heterostructure photocathode significantly improves the photocurrent density to -6.14 mAmiddotcm(-2) at -0.40 V-RHE by effective charge migration in the CZTS/CdS/ZnO/GO configuration, but the onset potential shifts only after application of the Al2O3 protection layer. Significant photocurrents of -29 mAmiddotcm(-2) at -0.40 V-RHE and -8 mAmiddotcm(-2) at 0 V-RHE are observed, with an onset potential of 0.7 V-RHE in CZTS/CdS/ZnO/GO/Al2O3. The heterostructure configuration and the GO co-catalyst reduce the charge-transfer resistance, while the Al2O3 top layer provides a stable photocurrent for a prolonged time (similar to 16 h). The GO co-catalyst increases the flat band potential from 0.26 to 0.46 V-RHE in CZTS/CdS/ZnO/GO, which supports the bias-induced band bending at the electrolyte-electrode interface.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.4
DOI: 10.1021/ACSAEM.2C01011
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“Topotactic redox cycling in SrFeO2.5+&delta, explored by 3D electron diffraction in different gas atmospheres”. Batuk M, Vandemeulebroucke D, Ceretti M, Paulus W, Hadermann J, Journal of materials chemistry A : materials for energy and sustainability (2022). http://doi.org/10.1039/D2TA03247C
Abstract: For oxygen conducting materials applied in solid oxide fuel cells and chemical-looping processes, the understanding of the oxygen diffusion mechanism and the materials’ crystal structure at different stages of the redox reactions is a key parameter to control their performance. In this paper we report the first ever in situ 3D ED experiment in a gas environment and with it uncover the structure evolution of SrFeO2.5 as notably different from that reported from in situ X-ray and in situ neutron powder diffraction studies in gas environments. Using in situ 3D ED on submicron sized single crystals obtained from a high quality monodomain SrFeO2.5 single crystal , we observe the transformation under O2 flow of SrFeO2.5 with an intra- and interlayer ordering of the left and right twisted (FeO4) tetrahedral chains (space group Pcmb) into consecutively SrFeO2.75 with space group Cmmm (at 350°C, 33% O2) and SrFeO3-δ with space group Pm3 ̅m (at 400°C, 100% O2). Upon reduction in H2 flow, the crystals return to the brownmillerite structure with intralayer order, but without regaining the interlayer order of the pristine crystals. Therefore, redox cycling of SrFeO2.5 crystals in O2 and H2 introduces stacking faults into the structure, resulting in an I2/m(0βγ)0s symmetry with variable β.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 11.9
DOI: 10.1039/D2TA03247C
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“3D-cavity-confined CsPbBr₃, quantum dots for visible-light-driven photocatalytic C(sp³)-H bond activation”. Gao Y-J, Jin H, Esteban DA, Weng B, Saha RA, Yang M-Q, Bals S, Steele JA, Huang H, Roeffaers MBJ, Carbon Energy , e559 (2024). http://doi.org/10.1002/CEY2.559
Abstract: Metal halide perovskite (MHP) quantum dots (QDs) offer immense potential for several areas of photonics research due to their easy and low-cost fabrication and excellent optoelectronic properties. However, practical applications of MHP QDs are limited by their poor stability and, in particular, their tendency to aggregate. Here, we develop a two-step double-solvent strategy to grow and confine CsPbBr3 QDs within the three-dimensional (3D) cavities of a mesoporous SBA-16 silica scaffold (CsPbBr3@SBA-16). Strong confinement and separation of the MHP QDs lead to a relatively uniform size distribution, narrow luminescence, and good ambient stability over 2 months. In addition, the CsPbBr3@SBA-16 presents a high activity and stability for visible-light-driven photocatalytic toluene C(sp(3))-H bond activation to produce benzaldehyde with similar to 730 mu mol g(-1) h(-1) yield rate and near-unity selectivity. Similarly, the structural stability of CsPbBr3@SBA-16 QDs is superior to that of both pure CsPbBr3 QDs and those confined in MCM-41 with 1D channels.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
DOI: 10.1002/CEY2.559
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“Single-layered imine-linked porphyrin-based two-dimensional covalent organic frameworks targeting CO₂, reduction”. Arisnabarreta N, Hao Y, Jin E, Salame A, Muellen K, Robert M, Lazzaroni R, Van Aert S, Mali KS, De Feyter S, Advanced energy materials (2024). http://doi.org/10.1002/AENM.202304371
Abstract: The reduction of carbon dioxide (CO2) using porphyrin-containing 2D covalent organic frameworks (2D-COFs) catalysts is widely explored nowadays. While these framework materials are normally fabricated as powders followed by their uncontrolled surface heterogenization or directly grown as thin films (thickness >200 nm), very little is known about the performance of substrate-supported single-layered (approximate to 0.5 nm thickness) 2D-COFs films (s2D-COFs) due to its highly challenging synthesis and characterization protocols. In this work, a fast and straightforward fabrication method of porphyrin-containing s2D-COFs is demonstrated, which allows their extensive high-resolution visualization via scanning tunneling microscopy (STM) in liquid conditions with the support of STM simulations. The as-prepared single-layered film is then employed as a cathode for the electrochemical reduction of CO2. Fe porphyrin-containing s2D-COF@graphite used as a single-layered heterogeneous catalyst provided moderate-to-high carbon monoxide selectivity (82%) and partial CO current density (5.1 mA cm(-2)). This work establishes the value of using single-layered films as heterogene ous catalysts and demonstrates the possibility of achieving high performance in CO2 reduction even with extremely low catalyst loadings.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 27.8
DOI: 10.1002/AENM.202304371
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“Effect of crystal structure on the electronic transport properties of the organometallic perovskite CH3NH3PbI3”. Berdiyorov GR, Madjet ME, El-Mellouhi F, Peeters FM, Solar energy materials and solar cells
T2 –, 2nd International Renewable and Sustainable Energy Conference (IRSEC), OCT 17-19, 2014, Ouarzazate, MOROCCO 148, 60 (2016). http://doi.org/10.1016/j.solmat.2015.09.006
Abstract: Using density-functional theory in combination with the nonequilibrium Green's function formalism, we study the effect of the crystal lattice structure of organometallic perovskite CH3NH3PbI3 on its electronic transport properties. Both dispersive interactions and spin-orbit coupling are taken into account in describing structural and electronic properties of the system. We consider two different phases of the material, namely the orthorhombic and cubic lattice structures, which are energetically stable at low (< 160 K) and high (> 330 K) temperatures, respectively. The sizable geometrical differences between the two structures in term of lattice parameters, PbI6 octahedral tilts, rotation and deformations, have considerable impact on the transport properties of the material. For example, at zero bias and for all considered electron energies, the cubic phase has a larger transmission than the orthorhombic one, although both show similar electronic densities of states. Depending on the applied voltage, the current in the cubic system can be several orders of magnitude larger as compared to the one obtained for the orthorhombic sample. We attribute this enhancement in the transmission to the presence of extended states in the cubic phase due to the symmetrically shaped and ordered PbI6 octaherdra. (C) 2015 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.784
Times cited: 16
DOI: 10.1016/j.solmat.2015.09.006
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“Effect of halide-mixing on the electronic transport properties of organometallic perovskites”. Berdiyorov GR, El-Mellouhi F, Madjet ME, Alharbi FH, Peeters FM, Kais S, Solar energy materials and solar cells
T2 –, 2nd International Renewable and Sustainable Energy Conference (IRSEC), OCT 17-19, 2014, Ouarzazate, MOROCCO 148, 2 (2016). http://doi.org/10.1016/j.solmat.2015.11.023
Abstract: Using density-functional theory in combination with the nonequilibrium Green's function formalism, we study the effect of iodide/chloride and iodide/bromide mixing on the electronic transport in lead based organometallic perovskite CH3NH3PbI3, which is known to be an effective tool to tune the electronic and optical properties of such materials. We found that depending on the level and position of the halide mixing, the electronic transport can be increased by more than a factor of 4 for a given voltage biasing. The largest current is observed for small concentration of bromide substitutions located at the equatorial sites. However, full halide substitution has a negative effect on the transport properties of this material: the current drops by an order of magnitude for both CH3NH3PbCl3 and CH3NH3PbBr3 samples. (C) 2015 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.784
Times cited: 23
DOI: 10.1016/j.solmat.2015.11.023
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“Large CO2 uptake on a monolayer of CaO”. Berdiyorov GR, Neek-Amal M, Hussein IA, Madjet ME, Peeters FM, Journal of materials chemistry A : materials for energy and sustainability 5, 2110 (2017). http://doi.org/10.1039/C6TA08810D
Abstract: Density functional theory calculations are used to study gas adsorption properties of a recently synthesized CaO monolayer, which is found to be thermodynamically stable in its buckled form. Due to its topology and strong interaction with the CO2 molecules, this material possesses a remarkably high CO2 uptake capacity (similar to 0.4 g CO2 per g adsorbent). The CaO + CO2 system shows excellent thermal stability (up to 1000 K). Moreover, the material is highly selective towards CO2 against other major greenhouse gases such as CH4 and N2O. These advantages make this material a very promising candidate for CO2 capture and storage applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 8.867
Times cited: 2
DOI: 10.1039/C6TA08810D
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“Mo2C as a high capacity anode material: a first-principles study”. Çakir D, Sevik C, Gulseren O, Peeters FM, Journal of materials chemistry A : materials for energy and sustainability 4, 6029 (2016). http://doi.org/10.1039/C6TA01918H
Abstract: The adsorption and diffusion of Li, Na, K and Ca atoms on a Mo2C monolayer are systematically investigated by using first principles methods. We found that the considered metal atoms are strongly bound to the Mo2C monolayer. However, the adsorption energies of these alkali and earth alkali elements decrease as the coverage increases due to the enhanced repulsion between the metal ions. We predict a significant charge transfer from the ad-atoms to the Mo2C monolayer, which indicates clearly the cationic state of the metal atoms. The metallic character of both pristine and doped Mo2C ensures a good electronic conduction that is essential for an optimal anode material. Low migration energy barriers are predicted as small as 43 meV for Li, 19 meV for Na and 15 meV for K, which result in the very fast diffusion of these atoms on Mo2C. For Mo2C, we found a storage capacity larger than 400 mA h g(-1) by the inclusion of multilayer adsorption. Mo2C expands slightly upon deposition of Li and Na even at high concentrations, which ensures the good cyclic stability of the atomic layer. The calculated average voltage of 0.68 V for Li and 0.30 V for Na ions makes Mo2C attractive for low charging voltage applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 8.867
Times cited: 202
DOI: 10.1039/C6TA01918H
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“MXenes/graphene heterostructures for Li battery applications : a first principles study”. Aierken Y, Sevik C, Gulseren O, Peeters FM, Çakir D, Journal of materials chemistry A : materials for energy and sustainability 6, 2337 (2018). http://doi.org/10.1039/C7TA09001C
Abstract: MXenes are the newest class of two-dimensional (2D) materials, and they offer great potential in a wide range of applications including electronic devices, sensors, and thermoelectric and energy storage materials. In this work, we combined the outstanding electrical conductivity, that is essential for battery applications, of graphene with MXene monolayers (M2CX2 where M = Sc, Ti, V and X = OH, O) to explore its potential in Li battery applications. Through first principles calculations, we determined the stable stacking configurations of M2CX2/graphene bilayer heterostructures and their Li atom intercalation by calculating the Li binding energy, diffusion barrier and voltage. We found that: (1) for the ground state stacking, the interlayer binding is strong, yet the interlayer friction is small; (2) Li binds more strongly to the O-terminated monolayer, bilayer and heterostructure MXene systems when compared with the OHterminated MXenes due to the H+ induced repulsion to the Li atoms. The binding energy of Li decreases as the Li concentration increases due to enhanced repulsive interaction between the positively charged Li ions; (3) Ti2CO2/graphene and V2CO2/graphene heterostructures exhibit large Li atom binding energies making them the most promising candidates for battery applications. When fully loaded with Li atoms, the binding energy is -1.43 eV per Li atom and -1.78 eV per Li atom for Ti2CO2/graphene and V2CO2/graphene, respectively. These two heterostructures exhibit a nice compromise between storage capacity and kinetics. For example, the diffusion barrier of Li in Ti2CO2/graphene is around 0.3 eV which is comparable to that of graphite. Additionally, the calculated average voltages are 1.49 V and 1.93 V for Ti2CO2/graphene and V2CO2/graphene structures, respectively; (4) a small change in the in-plane lattice parameters (<1%), interatomic bond lengths and interlayer distances (<0.5 angstrom) proves the stability of the heterostructures against Li intercalation, and the impending phase separation into constituent layers and capacity fading during charge-discharge cycles in real battery applications; (5) as compared to bare M2CX2 bilayers, M2CX2/graphene heterostructures have lower molecular mass, offering high storage capacity; (6) the presence of graphene ensures good electrical conductivity that is essential for battery applications. Given these advantages, Ti2CO2/graphene and V2CO2/graphene heterostructures are predicted to be promising for lithium-ion battery applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 8.867
Times cited: 131
DOI: 10.1039/C7TA09001C
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“High performance piezotronic spin transistors using molybdenum disulfide nanoribbon”. Yan XF, Chen Q, Li LL, Guo HZ, Peng JZ, Peeters FM, Nano Energy 75, 104953 (2020). http://doi.org/10.1016/J.NANOEN.2020.104953
Abstract: Two-dimensional (2D) materials are promising candidates for atomic-scale piezotronics and piezophototronics. Quantum edge states show fascinating fundamental physics such as nontrivial topological behavior and hold promising practical applications for low-power electronic devices. Here, using the tight-binding approach and quantum transport simulations, we investigate the piezotronic effect on the spin polarization of edge states in a zigzag-terminated monolayer MoS2 nanoribbon. We find that the strain-induced piezoelectric potential induces a phase transition of edge states from metal to semiconductor. However, in the presence of exchange field, edge states become semi-metallic with significant spin splitting and polarization that can be tuned by external strain. We show that quantum transport conductance exhibits a 100% spin polarization over a wide range of strain magnitudes. This effect is used in a propose prototype of piezotronic spin transistor. Our results provide a fundamental understanding of the piezotronic effect on edge states in zigzag monolayer MoS2 nanoribbons and are relevant for designing high-performance piezotronic spin devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 17.6
Times cited: 20
DOI: 10.1016/J.NANOEN.2020.104953
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“ZnN and ZnP as novel graphene-like materials with high Li-ion storage capacities”. Mortazavi B, Bafekry A, Shahrokhi M, Rabczuk T, Zhuang X, Materials today energy 16, Unsp 100392 (2020). http://doi.org/10.1016/J.MTENER.2020.100392
Abstract: In this work, we employed first-principles density functional theory (DFT) calculations to investigate the dynamical and thermal stability of graphene-like ZnX (X = N, P, As) nanosheets. We moreover analyzed the electronic, mechanical and optical properties of these novel two-dimensional (2D) systems. Acquired phonon dispersion relations reveal the absence of imaginary frequencies and thus confirming the dynamical stability of predicted monolayers. According to ab-initio molecular dynamics results however only ZnN and ZnP exhibit the required thermally stability. The elastic modulus of ZnN, ZnP and ZnAs are estimated to be 31, 21 and 17 N/m, respectively, and the corresponding tensile strengths values are 6.0, 4.9 and 4.0 N/m, respectively. Electronic band structure analysis confirms the metallic electronic character for the predicted monolayers. Results for the optical characteristics also indicate a reflectivity of 100% at extremely low energy levels, which is desirable for photonic and optoelectronic applications. According to our results, graphene-like ZnN and ZnP nanosheets can yield high capacities of 675 and 556 mAh/g for Li-ion storage, respectively. Acquired results confirm the stability and acceptable strength of ZnN and ZnP nanosheets and highlight their attractive application prospects in optical and energy storage systems.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 9.3
Times cited: 13
DOI: 10.1016/J.MTENER.2020.100392
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“Effect of hydrostatic pressure on lone pair activity and phonon transport in Bi₂O₂S”. Yedukondalu N, Pandey T, Roshan SCR, ACS applied energy materials 6, 2401 (2023). http://doi.org/10.1021/ACSAEM.2C03725
Abstract: Dibismuth dioxychalcogenides, Bi2O2Ch (Ch = S, Se, Te), are a promising class of materials for next-generation electronics and thermoelectrics due to their ultrahigh carrier mobility and excellent air stability. An interesting member of this family is Bi2O2S, which has a stereochemically active 6s2 lone pair of Bi3+ cations, heterogeneous bonding, and a high mass contrast between its constituent elements. In the present study, we have used first-principles calculations in combination with Boltzmann transport theory to systematically investigate the effect of hydrostatic pressure on lattice dynamics and phonon transport properties of Bi2O2S. We found that the ambient Pnmn phase has a low average lattice thermal conductivity (kappa l) of 1.71 W/(m K) at 300 K. We also predicted that Bi2O2S undergoes a structural phase transition from a low-symmetry (Pnmn) to a high-symmetry (I4/mmm) structure at around 4 GPa due to centering of Bi3+ cations with pressure. Upon compression, the lone pair activity of Bi3+ cations is suppressed, which increases kappa l by almost 3 times to 4.92 W/ (m K) at 5 GPa for the I4/mmm phase. The computed phonon lifetimes and Gru''neisen parameters show that anharmonicity decreases with increasing pressure due to further suppression of the lone pair activity and strengthening of intra-and intermolecular interactions, leading to an average room-temperature kappa l of 12.82 W/(m K) at 20 GPa. Overall, this study provides a comprehensive understanding of the effect of hydrostatic pressure on the stereochemical activity of the lone pair of Bi3+ cations and its implications on the phonon transport properties of Bi2O2S.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 6.4
DOI: 10.1021/ACSAEM.2C03725
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“A systematicalab-initioreview of promising 2D MXene monolayers towards Li-ion battery applications”. Yorulmaz U, Demiroglu I, Cakir D, Gulseren O, Sevik C, JPhys Energy 2, 032006 (2020). http://doi.org/10.1088/2515-7655/AB9FE3
Abstract: Two-dimensional materials have been attracting increasing interests because of their outstanding properties for Lithium-ion battery applications. In particular, a material family called MXenes (Mn+1Cn, where n = 1, 2, 3) have been recently attracted immense interest in this respect due to their incomparable fast-charging properties and high capacity promises. In this article, we review the state-of-the-art computational progress on Li-ion battery applications of MXene materials in accordance with our systematical DFT calculations. Structural, mechanical, dynamical, and electrical properties of 20 distinct MXene (M: Sc, Ti, V, Cr, Nb, Mo, Hf, Ta, W, and Zr) have been discussed. The battery performances of these MXene monolayers are further investigated by Li-ion binding energies, open circuit voltage values, and Li migration energy barriers. The experimental and theoretical progress up to date demonstrates particularly the potential of non-terminated or pristine MXene materials in Li ion-storage applications. Stability analyses show most of the pristine MXenes should be achievable, however susceptible to the development progress on the experimental growth procedures. Among pristine MXenes, Ti2C, V2C, Sc2C, and Zr2C compounds excel with their high charge/discharge rate prospect due to their extremely low Li diffusion energy barriers. Considering also their higher predicted gravimetric capacities, Sc, Ti, V, and Zr containing MXenes are more promising for their utilization in energy storage applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 6.9
DOI: 10.1088/2515-7655/AB9FE3
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“Achieving Fast Kinetics and Enhanced Li Storage Capacity for Ti3C2O2 by Intercalation of Quinone Molecules”. Siriwardane EMD, Demiroglu I, Sevik C, Cakir D, ACS applied energy materials 2, 1251 (2019). http://doi.org/10.1021/ACSAEM.8B01801
Abstract: Using first-principles calculations, we demonstrated that high lithium storage capacity and fast kinetics are achieved for Ti3C2O2 by preintercalating organic molecules. As a proof-of-concept, two different quinone molecules, namely 1,4-benzoquinone (C6H4O2) and tetrafluoro-1,4-benzoquinone (C6F4O2) were selected as the molecular linkers to demonstrate the feasibility of this interlayer engineering strategy for energy storage. As compared to Ti3C2O2 bilayer without linker molecules, our pillared structures facilitate a much faster ion transport, promising a higher charge/discharge rate for Li. For example, while the diffusion barrier of a single Li ion within pristine Ti3C2O2 bilayer is at least 1.0 eV, it becomes 0.3 eV in pillared structures, which is comparable and even lower than that of commercial materials. At high Li concentrations, the calculated diffusion barriers are as low as 0.4 eV. Out-of-plane migration of Li ions is hindered due to large barrier energy with a value of around 1-1.35 eV. Concerning storage capacity, we can only intercalate one monolayer of Li within pristine Ti3C2O2 bilayer. In contrast, pillared structures offer significantly higher storage capacity. Our calculations showed that at least two layers of Li can be intercalated between Ti3C2O2 layers without forming bulk Li and losing the pillared structure upon Li loading/unloading. A small change in the in-plane lattice parameters (<0.5%) and volume (<1.0%) and ab initio molecular dynamics simulations prove the stability of the pillared structures against Li intercalation and thermal effects. Intercalated molecules avoid the large contraction/expansion of the whole structure, which is one of the key problems in electrochemical energy storage. Pillared structures allow us to realize electrodes with high capacity and fast kinetics. Our results open new research paths for improving the performance of not only MXenes but also other layered materials for supercapacitor and battery applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1021/ACSAEM.8B01801
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“Analyzing a self-managed CHP system for greenhouse cultivation as a profitable way to reduce CO2-emissions”. Compernolle T, Witters N, Van Passel S, Thewys T, Energy 36, 1940 (2011). http://doi.org/10.1016/J.ENERGY.2010.02.045
Abstract: To counter global warming, a transition to a low-carbon economy is needed. The greenhouse sector can contribute by installing Combined Heat and Power (CHP) systems, known for their excellent energy efficiency. Due to the recent European liberalization of the energy market, glass horticulturists have the opportunity to sell excess electricity to the market and by tailored policy and support measures, regional governments can fill the lack of technical and economic knowledge, causing initial resistance. This research investigates the economic and environmental opportunities using two detailed cases applying a self managed cogeneration system. The Net Present Value is calculated to investigate the economic feasibility. The Primary Energy Saving, the CO2 Emission Reduction indicator and an Emission Balance are applied to quantify the environmental impact. The results demonstrate that a self-managed CHP system is economic viable and that CO2 emissions are reduced. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology
Impact Factor: 4.52
Times cited: 19
DOI: 10.1016/J.ENERGY.2010.02.045
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“Intensified swirling reactor for the dehydrogenation of LOHC”. Van Hoecke L, Kummamuru NB, Pourfallah H, Verbruggen SW, Perreault P, International journal of hydrogen energy , 1 (2023). http://doi.org/10.1016/J.IJHYDENE.2023.08.150
Abstract: In the recent advances towards more sustainable global energy supply, H2 is a possible alternative for large scale energy storage. In this view, Liquid Organic Hydrogen Carriers (LOHC) are a class of molecules that allow for easier long term energy storage compared to conventional H2 technologies. CFD simulations were used to showcase the hydrodynamics of the dehydrogenation of a LOHC in a new reactor unit, via a cold flow mock-up study. This reactor was designed to allow for a swirling motion of the liquid carrier material, favouring the removal of H2 gas from the flow and forcing the equilibrium of the reaction towards dehydrogenation, as well as to keep the catalyst particles in motion. The CFD simulations were validated qualitatively with experimental operation of the reactor, in a system with identical dimensionless numbers (Reynolds and Stokes), in order to use less costly products during the prototyping phase.
Keywords: A1 Journal article; Engineering sciences. Technology
Impact Factor: 7.2
DOI: 10.1016/J.IJHYDENE.2023.08.150
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“Engineering of hollow periodic mesoporous organosilica nanorods for augmented hydrogen clathrate formation”. Watson G, Kummamuru NB, Verbruggen SW, Perreault P, Houlleberghs M, Martens J, Breynaert E, Van Der Voort P, Journal of materials chemistry A : materials for energy and sustainability 11, 26265 (2023). http://doi.org/10.1039/D3TA05530B
Abstract: Hydrogen (H2) storage, in the form of clathrate hydrates, has emerged as an attractive alternative to classical storage methods like compression or liquefaction. Nevertheless, the sluggish enclathration kinetics along with low gas storage capacities in bulk systems is currently impeding the progress of this technology. To this end, unstirred systems coupled with porous materials have been shown to tackle the aforementioned drawbacks. In line with this approach, the present study explores the use of hydrophobic periodic organosilica nanoparticles, later denoted as hollow ring-PMO (HRPMO), for H2 storage as clathrate hydrates under mild operating conditions (5.56 mol% THF, 7 MPa, and 265–273 K). The surface of the HRPMO nanoparticles was carefully decorated/functionalized with THF-like moieties, which are well-known promoter agents in clathrate formation when applied in classical, homogeneous systems. The study showed that, while the non-functionalized HRPMO can facilitate the formation of binary H2-THF clathrates, the incorporation of surface-bound promotor structures enhances this process. More intriguingly, tuning the concentration of these surface-bound promotor agents on the HRPMO led to a notable effect on solid-state H2 storage capacities. An increase of 3% in H2 storage capacity, equivalent to 0.26 wt%, along with a substantial increase of up to 28% in clathrate growth kinetics, was observed when an optimal loading of 0.14 mmol g−1 of promoter agent was integrated into the HRPMO framework. Overall, the findings from this study highlight that such tuning effects in the solid-state have the potential to significantly boost hydrate formation/growth kinetics and H2 storage capacities, thereby opening new avenues for the ongoing development of H2 clathrates in industrial applications.
Keywords: A1 Journal article; Engineering sciences. Technology
Impact Factor: 11.9
DOI: 10.1039/D3TA05530B
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“Reducing winter peaks in electricity consumption: A choice experiment to structure demand response programs”. Srivastava A, Van Passel S, Kessels R, Valkering P, Laes E, Energy Policy 137, 111183 (2020). http://doi.org/10.1016/j.enpol.2019.111183
Abstract: Winter peaks in Belgian electricity demand are significantly higher than the summer peaks, creating a greater potential for imbalances between demand and supply. This potential is exacerbated because of the risk of outages in its ageing nuclear power plants, which are being phased out in the medium term. This paper conducts a choice experiment to investigate the acceptability of a load control-based demand response program in the winter months. It surveys 186 respondents on their willingness to accept limits on the use of home appliances in return for a compensation. Results indicate that respondents are most affected by the days of the week that their appliance usage would be curtailed, and by the compensation they would receive. The willingness to enroll in a program increases with age, environmental consciousness, home ownership, and lower privacy concerns. The analysis predicts that 95% of the sample surveyed could enroll in a daily load control program for a compen- sation of €41 per household per year. Thus while an initial rollout among older and more pro-environment homeowners could be successful, a wider implementation would require an explanation of its environmental and financial benefits to the population, and a greater consideration of their data privacy concerns.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
Impact Factor: 9
DOI: 10.1016/j.enpol.2019.111183
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“The path to sustainable energy supply systems: Proposal of an integrative sustainability assessment framework”. Buchmayr A, Verhofstadt E, Van Ootegem L, Sanjuan Delmás D, Thomassen G, Dewulf J, Renewable &, Sustainable Energy Reviews 138, 110666 (2021). http://doi.org/10.1016/j.rser.2020.110666
Abstract: Energy supply is essential for the functioning and well-being of a society. Decision-makers are faced with the challenge to balance burdens and benefits of energy supply practices with the aim to achieve environmental, economic, and social sustainability. Literature exhibits a broad variety of sustainability assessment frameworks for energy supply technologies. However, there is no consensus on which aspects need to be covered for a comprehensive assessment of sustainability. While some aspects, such as environmental emission damage, receive predominant attention, there is a lack of coverage and adequate quantification for others. This led in the past to an unbalanced basis for decision-making.
Based on an analysis of literature, 12 impact categories were identified for the assessment of energy technologies. The analysis included the judgement of quantification approaches regarding their significance for describing the impact categories and their maturity resulting in the proposal of 12 concrete indicators. A framework is proposed to manage and integrate the assessment of single impact categories. The framework produces normalized and weighted output indicators to use in the form of a dashboard or alternatively a single sustainability index for informed decision-making.
Finally, the proposed sustainability assessment framework relies on life cycle, local impact, and supply chain risks assessment. It consists of both well-established assessment methods as well as suggestions for new indicators in order to allow a full assessment of all impact categories. It thereby goes beyond the isolated assessment of impacts and offers the basis for comparison of complete energy supply mixes.
Keywords: A1 Journal Article; Engineering Management (ENM) ;
Impact Factor: 8.05
DOI: 10.1016/j.rser.2020.110666
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“External costs from fossil electricity generation : a review of the applied impact pathway approach”. Jorli M, Van Passel S, Saghdel HS, Energy &, Environment 29, 635 (2018). http://doi.org/10.1177/0958305X18761616
Abstract: This paper reviews and compares 11 studies that have estimated external costs of fossil electricity generation by benefits transfer. These studies include 13 countries and most of these countries are developing countries. The impact pathway approach is applied to estimate the environmental impact arising from fossil fuel-fired power plant's air emission and the related damages on human health. The estimated damages are used to value the monetary external costs from fossil fuel electricity generation. The estimated external costs in the 13 countries vary from 0.51 to 213.5 USD (2005) per MWh due to differences in fossil fuel quality, location, technology, and efficiency of power plants and additionally differences in assumptions, monetization values, and impact estimations. Accounting for these externalities can indicate the actual costs of fossil energy. The results can be applied by policy makers to take measures to avoid additional costs and to apply newer and cleaner energy sources. The described methods in the selected studies for estimating the external costs with respect to incomplete local data can be applied as a useful example for other developing countries.
Keywords: A1 Journal article; Engineering Management (ENM)
Impact Factor: 0.302
Times cited: 3
DOI: 10.1177/0958305X18761616
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“A cross-European analysis of the impact of electricity pricing on battery uptake in residential microgrids with photovoltaic units”. Saviuc I, Milis K, Peremans H, Van Passel S, Journal of Sustainable Development of Energy, Water and Environment Systems 9, 1080368 (2021). http://doi.org/10.13044/J.SDEWES.D8.0368
Abstract: As decentralized electricity generation is supporting grid development into the prosumer era, this paper investigates the economic viability of adding batteries to residential microgrids powered by photovoltaic units, under various electricity pricing schemes. Batteries bring the benefits of grid-stabilization and congestion relief, and they are also becoming cheaper. The problem identified is that the main grid effectively acts as a lossless storage system, especially under the net-metering scheme, whereas using a battery involves investment costs and energy losses. This mismatch is addressed by analysing residential microgrid projects under seven tariff designs, each in seven countries of the European Union, and compare the economic viability of photovoltaic systems with and without batteries. The findings show that the conditions most favourable to batteries are given by a capacity tariff scheme allowing price arbitrage. Based on these findings, the paper discusses possibilities for further support in order to bring the economic viability of microgrids with batteries on par with that of microgrids without batteries.
Keywords: A1 Journal article; Engineering Management (ENM)
DOI: 10.13044/J.SDEWES.D8.0368
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“Ti4O7 supported Ru@Pt core–shell catalyst for CO-tolerance in PEM fuel cell hydrogen oxidation reaction”. L Zhang J Kim J Zhang F Nan N Gauquelin GA Botton P He R Bashyam S Knights, Applied Energy 103, 507 (2013). http://doi.org/10.1016/j.apenergy.2012.10.017
Abstract: A new method is developed for synthesizing Ti4O7 supported Ru@Pt core–shell catalyst (Ru@Pt/Ti4O7) through pyrolysis followed by microwave irradiation. The purpose is to improve the Ru durability of PtRu from core–shell structure and strong bonding to Ti4O7 oxide. In this method, the first step is to co-reduce the mixture of ruthenium precursor and TiO2 in a H2 reducing atmosphere under heat-treatment to obtain a Ru core on Ti4O7 support, and the second step is to create a shell of platinum via microwave irradiation. Energy dispersive X-ray spectrometry, X-ray Diffraction, High-resolution Scanning Transmission Electron Microscopy with the high-angle annular dark-field method and Electron Energy-Loss Spectroscopy are used to demonstrate that this catalyst with larger particles has a core–shell structure with a Ru core and a Pt shell. Electrochemical measurements show Ru@Pt/Ti4O7 catalyst has a higher CO-tolerance capability than that of PtRu/C alloy catalyst.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Times cited: 33
DOI: 10.1016/j.apenergy.2012.10.017
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“Plasma-assisted synthesis of Ag/ZnO nanocomposites : first example of photo-induced H2 production and sensing”. Simon Q, Barreca D, Bekermann D, Gasparotto A, Maccato C, Comini E, Gombac V, Fornasiero P, Lebedev OI, Turner S, Devi A, Fischer RA, Van Tendeloo G, International journal of hydrogen energy 36, 15527 (2011). http://doi.org/10.1016/j.ijhydene.2011.09.045
Abstract: Ag/ZnO nanocomposites were developed by a plasma-assisted approach. The adopted strategy exploits the advantages of Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) for the growth of columnar ZnO arrays on Si(100) and Al2O3 substrates, in synergy with the infiltration power of the Radio Frequency (RF)-sputtering technique for the subsequent dispersion of different amounts of Ag nanoparticles (NPs). The resulting composites, both as-prepared and after annealing in air, were thoroughly characterized with particular attention on their morphological organization, structure and composition. For the first time, the above systems have been used as catalysts in the production of hydrogen by photo-reforming of alcoholic solutions, yielding a stable H2 evolution even by the sole use of simulated solar radiation. In addition, Ag/ZnO nanocomposites presented an excellent response in the gas-phase detection of H2, opening attractive perspectives for advanced technological applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.582
Times cited: 62
DOI: 10.1016/j.ijhydene.2011.09.045
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“Role of the carbon support on the oxygen reduction and evolution activities in LaNiO3 composite electrodes in alkaline solution”. Alexander CT, Abakumov AM, Forslund RP, Johnston KP, Stevenson KJ, ACS applied energy materials 1, 1549 (2018). http://doi.org/10.1021/ACSAEM.7B00339
Abstract: Metal-air batteries and fuel cells show a great deal of promise in advancing low-cost, high-energy-density charge storage solutions for sustainable energy applications. To improve the activities and stabilities of electrocatalysts for the critical oxygen reduction and evolution reactions (ORR and OER, respectively), a greater understanding is needed of the catalyst/carbon interactions and carbon stability. Herein, we report how LaNiO3 (LNO) supported on nitrogen-doped carbon nanotubes (N-CNT) made from a high-yield synthesis lowers the overpotential for both the OER and ORR markedly to enable a low bifunctional window of 0.81 V at only a 51 mu g cm(-2) mass loading. Furthermore, the addition of LNO to the N-CNTs improves the galvanostatic stability for the OER by almost 2 orders of magnitude. The nanoscale geometries of the perovskites and the CNTs enhance the number of metal-support and charge transfer interactions and thus the activity. We use rotating ring disk electrodes (RRDEs) combined with Tafel slope analysis and ICP-OES to quantitatively separate current contributions from the OER, carbon oxidation, and even anodic iron leaching from carbon nanotubes.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1021/ACSAEM.7B00339
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“Enhanced electrical properties of Bi2-xSbxTe3 nanoflake thin films through interface engineering”. Wu X, Ding J, Cui W, Lin W, Xue Z, Yang Z, Liu J, Nie X, Zhu W, Van Tendeloo G, Sang X, Energy &, environment materials , e12755 (2024). http://doi.org/10.1002/EEM2.12755
Abstract: The structure-property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure. Designing thermoelectric materials with a simple, structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties. Here, we synthesized Bi2-xSbxTe3 (x = 0, 0.1, 0.2, 0.4) nanoflakes using a hydrothermal method, and prepared Bi2-xSbxTe3 thin films with predominantly (0001) interfaces by stacking the nanoflakes through spin coating. The influence of the annealing temperature and Sb content on the (0001) interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy. Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the (0001) interface. As such it enhances interfacial connectivity and improves the electrical transport properties. Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient. Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient, the maximum power factor of the Bi1.8Sb0.2Te3 nanoflake films reaches 1.72 mW m(-1) K-2, which is 43% higher than that of a pure Bi2Te3 thin film.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1002/EEM2.12755
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“Assessing the future of second-generation bioethanol by 2030 : a techno-economic assessment integrating technology learning curves”. Vasilakou K, Nimmegeers P, Thomassen G, Billen P, Van Passel S, Applied energy 344, 121263 (2023). http://doi.org/10.1016/J.APENERGY.2023.121263
Abstract: Lignocellulosic biomass is the most abundant source of renewable biomass and is seen as a high-potential replacement for petroleum-based resources. The conversion technologies to advanced biofuels are still at a low maturity level, thus allowing for future cost reductions through technological learning. This fact is barely considered in state-of-the-art techno-economic assessments and a structured approach to account for technological learning in techno-economic assessments is needed. In this study, a framework for techno-economic assessments of advanced biofuels, integrating learning curves, is proposed. As a validation of this framework, the economic feasibility of the valorization of corn stover for the production of second-generation bioethanol in Belgium is studied. Process flowsheet simulations in Aspen Plus are developed, with an emphasis on the comparison of four different pretreatment technologies and two plant capacities at 156 dry kt biomass/y and 667 dry kt/y. The dilute acid pretreatment model of the large-scale biorefinery required the lowest minimum learning rate to reach an economically feasible biorefinery by 2030, being 3.9%, almost half as the one calculated for the smaller scale plant. This learning rate seems to be achievable based on learning rates commonly estimated in literature. We conclude that there is a potential for advanced ethanol production in Belgium under the current state of technology for large-scale biorefineries, which require additional biomass imports, when accounting for future cost reductions through learning
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Impact Factor: 11.2
DOI: 10.1016/J.APENERGY.2023.121263
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“Geospatial environmental techno-economic assessment of pretreatment technologies for bioethanol production”. Vasilakou K, Nimmegeers P, Billen P, Van Passel S, Renewable and sustainable energy reviews 187, 113743 (2023). http://doi.org/10.1016/J.RSER.2023.113743
Abstract: Second-generation biofuels, starting from lignocellulosic biomass, are considered as a renewable alternative for fossil fuels with lower environmental impact and potentially higher supply and energy security. The economic and environmental performance of second-generation bioethanol production from corn stover in the European Union (EU) is studied, starting in Belgium as base case. A comparative environmental techno-economic assessment has been conducted, with process simulations in Aspen Plus and corn stover availability data in thirteen EU countries to calculate minimum ethanol selling prices (MESP) and Greenhouse gas emissions (GHGe). In this analysis, the emphasis is on the comparison of different pretreatment technologies, namely (i) dilute acid, (ii) alkaline, (iii) steam explosion and (iv) liquid hot water. Dilute acid showed the best economic and environmental performance for the base case scenario. Within the EU, Hungary and Romania presented the lowest MESP for the steam explosion model at 0.39 and 0.43 EUR/L respectively. Poland showed the lowest GHGe, at 0.46 kg CO2eq/L for the alkaline model, mainly due to the avoided product allocation on electricity and its high carbon intensity in the electricity generation sector. The second lowest GHGe were obtained in France for the dilute acid model and are attributed to its low agricultural emissions intensity. This study identifies a location-dependence of the economic and environmental performance of pretreatment technologies, which can be extrapolated from the EU to other large regions around the world and should be taken into consideration by decision-makers.
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Impact Factor: 15.9
DOI: 10.1016/J.RSER.2023.113743
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“A Pareto aggregation approach for environmental-economic multi-objective optimization applied on a second-generation bioethanol production model”. Vasilakou K, Billen P, Van Passel S, Nimmegeers P, Energy conversion and management 303, 118184 (2024). http://doi.org/10.1016/J.ENCONMAN.2024.118184
Abstract: Multi-objective optimization is an important decision-making tool for energy processes, as multiple targets need to be achieved. These objectives are usually conflicting since a single solution cannot be optimal for all objectives, resulting in a set of Pareto-optimal solutions. Multiple indicators might be available to describe a sustainability objective, such as the environmental impact which is commonly evaluated by performing a life cycle assessment. In this study, Pareto aggregation is proposed as a method which employs a novel multi-objective optimization-based approach as an alternative to the classically used aggregation in life cycle assessment. This method identifies conflicting environmental indicators and performs an aggregation among those that require a trade-off. An environmental-economic optimization of a second-generation bioethanol plant is used to illustrate and evaluate the proposed method. Process parameters from a biochemical conversion pathway flowsheet simulation model are chosen as optimization variables. To reduce the computational time, surrogate models, based on artificial neural networks, are used. Out of the eighteen ReCiPe Midpoint environmental indicators, five were identified as conflicting, resulting in an aggregated environmental objective, which was then traded off with the economic objective function, chosen as the levelized cost of ethanol. Comparison with the widely used single-score EcoIndicator99 showed that the Pareto aggregation method can reduce most of the environmental indicators by up to 6.5%. This research provides an insight on non-redundant objective functions, aiming at reducing the dimensionality of multi-objective optimization problems, while taking into consideration decision-makers’ preferences.
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Impact Factor: 10.4
DOI: 10.1016/J.ENCONMAN.2024.118184
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“Young people's acceptance of bioenergy and the influence of attitude strength on information provision”. Van Dael M, Lizin S, Swinnen G, Van Passel S, Renewable Energy 107, 417 (2017). http://doi.org/10.1016/J.RENENE.2017.02.010
Abstract: This study investigated the effects of using a standardized PowerPoint lecture to provide young people with nuanced information about bioenergy. The studys aim was to understand the relationship between knowledge and participants perception of bioenergy, and the relationship of the latter to participants attitude strength and intention to use and learn about bioenergy. Data were collected from 715 participants using a survey instrument that contained mainly Likert-scale questions. Data were then processed using partial least squares structural equation modelling. Results show that providing such information increases knowledge about bioenergy, but does relatively little to create a more positive perception of bioenergy. In turn, having a more positive view about bioenergy would lead to a higher intention to use bioenergy. Attitude strength was found to mediate the previous relationship and decreases the strength of the relationship between perception and intention to use. Results also show that the lecture weakly contributed to building attitude strength, rendering opinion change less likely in the future. We conclude that listening to a lecture on bioenergy slightly improves peoples perception of bioenergy, makes it more likely that people maintain such a disposition, and translates into a slightly higher intention to use bioenergy.
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 4.357
Times cited: 10
DOI: 10.1016/J.RENENE.2017.02.010
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