“Of enzyme use in cost-effective high solid simultaneous saccharification and fermentation processes”. Sóti V, Lenaerts S, Cornet I, Journal of biotechnology 270, 70 (2018). http://doi.org/10.1016/J.JBIOTEC.2018.01.020
Abstract: Enzyme cost is considered to be one of the most significant factors defining the final product price in lignocellulose hydrolysis and fermentation. Enzyme immobilization and recycling can be a tool to decrease costs. However, high solid loading is a key factor towards high product titers, and recovery of immobilized enzymes from this thick liquid is often overlooked. This paper aims to evaluate the economic feasibility of immobilized enzymes in simultaneous saccharification and fermentation (SSF) of lignocellulose biomass in general, as well as the recuperation of magnetic immobilized enzymes (m-CLEAs) during high solid loading in simultaneous saccharification, detoxification and fermentation processes (SSDF) of lignocellulose biomass. Enzyme prices were obtained from general cost estimations by Klein-Marcuschamer et al. [Klein-Marcuschamer et al. (2012) Biotechnol. Bioeng. 109, 10831087]. During enzyme cost analysis, the influence of inoculum recirculation as well as a shortened fermentation time was explored. Both resulted in 15% decrease of final enzyme product price. Enzyme recuperation was investigated experimentally and 99.5 m/m% of m-CLEAs was recovered from liquid medium in one step, while 88 m/m% could still be recycled from a thick liquid with high solid concentrations (SSF fermentation broth). A mathematical model was constructed to calculate the cost of immobilized and free enzyme utilization and showed that, with current process efficiencies and commercial enzyme prices, the cost reduction obtained by enzyme immobilization can reach around 60% compared to free enzyme utilization, while lower enzyme prices will result in a lower percentage of immobilization related savings, but overall enzyme costs will decrease significantly. These results are applied in a case study, estimating the viability of shifting from sugar to lignocellulose substrate for a 100 t lactic acid fermentation batch. It was concluded that it will only be economically feasible if the enzymes are produced at the most optimistic variable cost and either the activity of the immobilized catalyst or the recovery efficiency is further increased.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE)
Impact Factor: 2.599
Times cited: 6
DOI: 10.1016/J.JBIOTEC.2018.01.020
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“Hierarchical design in nanoporous metals”. Ying J, Lenaerts S, Symes MD, Yang X-Y, Advanced Science 9, 2106117 (2022). http://doi.org/10.1002/ADVS.202106117
Abstract: Hierarchically porous metals possess intriguing high accessibility of matter molecules and unique continuous metallic frameworks, as well as a high level of exposed active atoms. High rates of diffusion and fast energy transfer have been important and challenging goals of hierarchical design and porosity control with nanostructured metals. This review aims to summarize recent important progress toward the development of hierarchically porous metals, with special emphasis on synthetic strategies, hierarchical design in structure-function and corresponding applications. The current challenges and future prospects in this field are also discussed.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 15.1
DOI: 10.1002/ADVS.202106117
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“Plasmonic gold-embedded TiO2 thin films as photocatalytic self-cleaning coatings”. Peeters H, Keulemans M, Nuyts G, Vanmeert F, Li C, Minjauw M, Detavernier C, Bals S, Lenaerts S, Verbruggen SW, Applied Catalysis B-Environmental 267, 118654 (2020). http://doi.org/10.1016/j.apcatb.2020.118654
Abstract: Transparent photocatalytic TiO2 thin films hold great potential in the development of self-cleaning glass sur-
faces, but suffer from a poor visible light response that hinders the application under actual sunlight. To alleviate this problem, the photocatalytic film can be modified with plasmonic nanoparticles that interact very effectively with visible light. Since the plasmonic effect is strongly concentrated in the near surroundings of the nano- particle surface, an approach is presented to embed the plasmonic nanostructures in the TiO2 matrix itself, rather than deposit them loosely on the surface. This way the interaction interface is maximised and the plasmonic effect can be fully exploited. In this study, pre-fabricated gold nanoparticles are made compatible with the organic medium of a TiO2 sol-gel coating suspension, resulting in a one-pot coating suspension. After spin coating, homogeneous, smooth, highly transparent and photoactive gold-embedded anatase thin films are ob- tained.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 22.1
Times cited: 57
DOI: 10.1016/j.apcatb.2020.118654
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“Atomic layer deposition-based synthesis of photoactive TiO2 nanoparticle chains by using carbon nanotubes as sacrificial templates”. Deng S, Verbruggen SW, He Z, Cott DJ, Vereecken PM, Martens JA, Bals S, Lenaerts S, Detavernier C, RSC advances 4, 11648 (2014). http://doi.org/10.1039/c3ra42928h
Abstract: Highly ordered and self supported anatase TiO2 nanoparticle chains were fabricated by calcining conformally TiO2 coated multi-walled carbon nanotubes (MWCNTs). During annealing, the thin tubular TiO2 coating that was deposited onto the MWCNTs by atomic layer deposition (ALD) was transformed into chains of TiO2 nanoparticles ([similar]12 nm diameter) with an ultrahigh surface area (137 cm2 per cm2 of substrate), while at the same time the carbon from the MWCNTs was removed. Photocatalytic tests on the degradation of acetaldehyde proved that these forests of TiO2 nanoparticle chains are highly photoactive under UV light because of their well crystallized anatase phase.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.108
Times cited: 45
DOI: 10.1039/c3ra42928h
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“Titania-functionalized diatom frustules as photocatalyst for indoor air purification”. Ouwehand J, Van Eynde E, De Canck E, Lenaerts S, Verberckmoes A, Van der Voort P, Applied catalysis : B : environmental 226, 303 (2018). http://doi.org/10.1016/J.APCATB.2017.12.063
Abstract: Diatom frustules were extracted from the species Thalassiosira pseudonana and functionalized with titania to be used as photocatalysts in the abatement of acetaldehyde. The synthetic procedure is water-based and environmentally friendly. The synthesis parameters were optimized to give the highest possible photocatalytic activity. The optimized material, visualized with TEM and STEM-EDX, shows the TiO2 nanoparticles grafted inside the frustule pores, as well as on the silica surface. The titania particles, stabilized by the frustules, are 2.5 times more active than the P25 benchmark material. The photocatalyst is then tested in conditions of elevated relative humidity, to simulate indoor air. The catalytic activity only shows a minor decrease at 50% relative humidity, which is a better result than for the P25 benchmark. When tested over an extended period of time, the photocatalyst only shows a minor decrease in activity.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 4
DOI: 10.1016/J.APCATB.2017.12.063
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“Leaf accumulation of atmospheric dust : biomagnetic, morphological and elemental evaluation using SEM, ED-XRF and HR-ICP-MS”. Castanheiro A, Hofman J, Nuyts G, Joosen S, Spassov S, Blust R, Lenaerts S, De Wael K, Samson R, Atmospheric Environment 221, 117082 (2020). http://doi.org/10.1016/J.ATMOSENV.2019.117082
Abstract: Atmospheric dust deposition on plants enables the collection of site-specific particulate matter (PM). Knowing the morphology and composition of PM aids in disclosing their emitting sources as well as the associated human health risk. Therefore, this study aimed for a leaf-level holistic analysis of dust accumulation on plant leaves. Plant species (ivy and strawberry) with distinct leaf macro- and micro-morphology were exposed during 3 months at a moderate road traffic site in Antwerp, Belgium. Leaves collected every three weeks were analyzed for their magnetic signature, morphology and elemental content, by a combination of techniques (biomagnetic analyses, ED-XRF, HR-ICP-MS, SEM). Dust accumulation on the leaves was observed both visually (SEM) and magnetically, while the metal enrichment was limited (only evident for Cr) and more variable over time. Temporal dynamics during the second half of the exposure period, due to precipitation events and reduction of atmospheric pollution input, were evidenced in our results (elements/magnetically/SEM). Ivy accumulated more dust than strawberry leaves and seemed less susceptible to wash-off, even though strawberry leaves contain trichomes and a rugged micromorphology, leaf traits considered to be important for capturing PM. The magnetic enrichment (in small-grained, SD/PSD magnetite particles), on the other hand, was not species-specific, indicating a common contributing source. Variations in pollution contributions, meteorological phenomena, leaf traits, particle deposition (and encapsulation) versus micronutrients depletion, are discussed in light of the conducted monitoring campaign. Although not completely elucidative, the complex, multifactorial process of leaf dust accumulation can better be understood through a combination of techniques.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5
DOI: 10.1016/J.ATMOSENV.2019.117082
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“Microwave-assisted synthesis of mesoporous titania with increased crystallinity, specific surface area, and photocatalytic activity”. Meire M, Verbruggen SW, Lenaerts S, Lommens P, Van Der Voort P, Van Driessche I, Journal of materials science 51, 9822 (2016). http://doi.org/10.1007/S10853-016-0215-Y
Abstract: Mesoporous titanium dioxide is a material finding its use in a wide range of applications. For many of these, it is important to achieve a high degree of crystallinity in the material. It is generally accepted that the use of the soft templating approach to synthesize mesoporous titania, results in a compromise between crystallinity and specific surface area due to thermal instability of the used templates. In this paper, we explore how the use of microwave irradiation can influence the crystallinity, specific surface area, and the electronic properties of mesoporous titania. Therefore, we combined microwave radiation with an evaporation-induced self-assembly (EISA) synthesis. We show that additional microwave treatment at carefully chosen synthesis steps can enhance the crystallinity with 20 % without causing significant loss of surface area (>360 m2/g). Surface photovoltage measurements were used to investigate the electronic properties. The photocatalytic activity of the samples was evaluated in aqueous media by following the degradation of an industrial dye, methylene blue, and the herbicide isoproturon under UV irradiation and in gaseous media looking at the degradation of acetaldehyde, a common indoor pollutant under UVA irradiation. In all cases, the microwave treatment results in more active materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.599
Times cited: 8
DOI: 10.1007/S10853-016-0215-Y
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“Finding the optimal fatty acid composition for biodiesel improving the emissions of a one-cylinder diesel generator”. Maes RR, Potters G, Fransen E, Cayetano FC, Van Schaeren R, Lenaerts S, Sustainability 13, 12089 (2021). http://doi.org/10.3390/SU132112089
Abstract: Nitrogen oxides (NOx) and particulate matter (PM) currently are the main pollutants emitted by diesel engines. While there is a start in using hybrid and electric cars, ships will still be fueled by mineral oil products. In the quest to achieve zero-pollution and carbon-free shipping, alternative forms of energy carriers must be found to replace the commonly used mineral oil products. One of the possible alternative fuels is biodiesel. This paper explores the optimization of the composition of biodiesel in order to reduce the concentration of particulate matter and NOx in exhaust gases of a one-cylinder diesel generator.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.789
DOI: 10.3390/SU132112089
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“Ultrafast screening of commercial sorbent materials for VOC adsorption using real-time FTIR spectroscopy”. Blommaerts N, Dingenen F, Middelkoop V, Savelkouls J, Goemans M, Tytgat T, Verbruggen SW, Lenaerts S, Separation and purification technology 207, 284 (2018). http://doi.org/10.1016/J.SEPPUR.2018.06.062
Abstract: Recovery of valuable volatile organic compounds (VOCs) from waste streams is of great industrial importance. Adsorption on zeolites offers an economically and environmentally friendly alternative to conventional activated carbon. When evaluating the suitability of a given zeolite for a particular adsorption application, its adsorption capacity has to be determined. This is traditionally achieved using gas chromatography as an analysis tool, yielding only a few discrete sampling points that constitute the adsorption profile. Meanwhile, only low flow rates and low concentrations of volatile organics can be used, rendering the procedure troublesome and time consuming. Herein, we propose a tool for the fast screening of a large amount of zeolites using on-line and quasi real-time Fourier Transform Infrared Spectroscopy (FTIR). The technique was used to determine the adsorption capacity of three different commercial zeolites and two silica gels, for five industrially relevant VOCs: acetone; methanol; isohexane; isopentane; and toluene. A series of rapid measurements of the individual adsorption capacities were carried out to obtain a detailed overview of the versatility of the proposed method for the characterization of multi-component and multi-sorption bed systems.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.359
Times cited: 5
DOI: 10.1016/J.SEPPUR.2018.06.062
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“Silver-polymer core-shell nanoparticles for ultrastable plasmon-enhanced photocatalysis”. Asapu R, Claes N, Bals S, Denys S, Detavernier C, Lenaerts S, Verbruggen SW, Applied catalysis : B : environmental 200, 31 (2017). http://doi.org/10.1016/j.apcatb.2016.06.062
Abstract: Affordable silver-polymer core-shell nanoparticles are prepared using the layer-by-layer (LbL) technique. The metallic silver core is encapsulated with an ultra-thin protective shell that prevents oxidation and clustering without compromising the plasmonic properties. The core-shell nanoparticles retain their plasmonic near field enhancement effect, as studied from finite element numerical simulations. Control over the shell thickness up to the sub-nanometer level is there for key. The particles are used to prepare a plasmonic Ag-TiO2 photocatalyst of which the gas phase photocatalytic activity is monitored over a period of four months. The described system outperforms pristine TiO2 and retains its plasmonic enhancement in contrast to TiO2 modified with bare silver nanoparticles. With this an important step is made toward the development of long-term stable plasmonic (photocatalytic) applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 45
DOI: 10.1016/j.apcatb.2016.06.062
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“Concept and validation of a fully automated photocatalytic test setup”. Tytgat T, Hauchecorne B, Smits M, Verbruggen S, Lenaerts S, Journal of laboratory automation 17, 134 (2012). http://doi.org/10.1177/2211068211424554
Abstract: Photocatalytic activity can be studied by several methods, each with its own strengths and weaknesses. To study photocatalytic activity in an easy, user-friendly, and realistic way, a completely new setup has been built. The setup is modularly constructed around Fourier transform infrared spectroscopy (FTIR) spectroscopy at the heart of it, resulting in great versatility. Complementary software has been written for automatic control of the setup and for processing the generated data. Two pollutants, oil and n-octane, are tested to validate the performance of the setup. These validation experiments confirm the usefulness and added value of the setup in general and of the FTIR detection methodology as well. It becomes clear that a system of online measurements with good repeatability, accuracy, and user-friendliness has been created.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.85
Times cited: 15
DOI: 10.1177/2211068211424554
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“Study of (ir)reversible fouling in MBRs under various operating conditions using new on-line fouling sensor”. Huyskens C, Lenaerts S, Brauns E, Diels L, de Wever H, Separation and purification technology 81, 208 (2011). http://doi.org/10.1016/J.SEPPUR.2011.07.031
Abstract: In this study, a new fouling sensor was validated under different conditions of hydraulic (HRT) and sludge retention time (SRT). The MBR-VFM (membrane bioreactor-VITO Fouling Measurement) allows the simultaneous determination of the physically reversible and irreversible fouling potential of a mixed liquor during a single crossflow filtration test. In accordance with the on-line filtration behavior, the measured reversible and irreversible fouling propensities differed significantly between MBRs operated at different combinations of HRT-SRT. Moreover, a significant negative correlation was found between the on-line permeability and the reversible and irreversible fouling propensity measured by the MBR-VFM. This corresponded to observations made on membrane recovery after physical or chemical cleaning actions. Higher reversible and irreversible fouling were observed at lower HRT, presumably as a consequence of increased concentrations of foulants present. The effect of SRT was much smaller and restricted to the reversible fouling component. Possible explanations for the increased fouling at prolonged SRT are the higher sludge and colloid concentration and the smaller floc size. It can be concluded that the MBR-VFM is a useful tool to monitor fluctuations in a mixed liquors (ir)reversible fouling potential and can contribute to a deeper understanding of the occurring fouling phenomena.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.359
Times cited: 15
DOI: 10.1016/J.SEPPUR.2011.07.031
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“Plasmonic ‘rainbow&rsquo, photocatalyst with broadband solar light response for environmental applications”. Verbruggen SW, Keulemans M, Goris B, Blommaerts N, Bals S, Martens JA, Lenaerts S, Applied catalysis : B : environmental 188, 147 (2016). http://doi.org/10.1016/j.apcatb.2016.02.002
Abstract: We propose the concept of a ‘rainbow’ photocatalyst that consists of TiO2 modified with gold-silver alloy nanoparticles of various sizes and compositions, resulting in a broad plasmon absorption band that covers the entire UV–vis range of the solar spectrum. It is demonstrated that this plasmonic ‘rainbow’ photocatalyst is 16% more effective than TiO2 P25 under both simulated and real solar light for pollutant degradation at the solid-gas interface. With this we provide a promising strategy to maximize the spectral response for solar to chemical energy conversion.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 47
DOI: 10.1016/j.apcatb.2016.02.002
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“Integration of a photocatalytic multi-tube reactor for indoor air purification in HVAC systems : a feasibility study”. van Walsem J, Roegiers J, Modde B, Lenaerts S, Denys S, Environmental Science and Pollution Research 25, 18015 (2018). http://doi.org/10.1007/S11356-018-2017-Z
Abstract: This work is focused on an in-depth experimental characterization of multi-tube reactors for indoor air purification integrated in ventilation systems. Glass tubes were selected as an excellent photocatalyst substrate to meet the challenging requirements of the operating conditions in a ventilation system in which high flow rates are typical. Glass tubes show a low-pressure drop which reduces the energy demand of the ventilator, and additionally, they provide a large exposed surface area to allow interaction between indoor air contaminants and the photocatalyst. Furthermore, the performance of a range of P25-loaded sol-gel coatings was investigated, based on their adhesion properties and photocatalytic activities. Moreover, the UV light transmission and photocatalytic reactor performance under various operating conditions were studied. These results provide vital insights for the further development and scaling up of multi-tube reactors in ventilation systems which can provide a better comfort, improved air quality in indoor environments, and reduced human exposure to harmful pollutants.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.741
Times cited: 3
DOI: 10.1007/S11356-018-2017-Z
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“Photocatalytic removal of soot : unravelling of the reaction mechanism by EPR and in situ FTIR spectroscopy”. Smits M, Ling Y, Lenaerts S, Van Doorslaer S, ChemPhysChem : a European journal of chemical physics and physical chemistry 13, 4251 (2012). http://doi.org/10.1002/CPHC.201200674
Abstract: Photocatalytic soot oxidation is studied on P25 TiO2 as an important model reaction for self-cleaning processes by means of electron paramagnetic resonance (EPR) and Fourier transform infrared (FTIR) spectroscopy. Contacting of carbon black with P25 leads on the one hand to a reduction of the local dioxygen concentration in the powder. On the other hand, the weakly adsorbed radicals on the carbon particles are likely to act as alternative traps for the photogenerated conduction-band electrons. We find furthermore that the presence of dioxygen and oxygen-related radicals is vital for the photocatalytic soot degradation. The complete oxidation of soot to CO2 is evidenced by in situ FTIR spectroscopy, no intermediate CO is detected during the photocatalytic process.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.075
Times cited: 9
DOI: 10.1002/CPHC.201200674
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“Plasma-enhanced atomic layer deposition of silver using Ag(fod)(PEt3) and NH3-plasma”. Minjauw MM, Solano E, Sree SP, Asapu R, Van Daele M, Ramachandran RK, Heremans G, Verbruggen SW, Lenaerts S, Martens JA, Detavernier C, Dendooven J, Chemistry of materials 29, 7114 (2017). http://doi.org/10.1021/ACS.CHEMMATER.7B00690
Abstract: A plasma-enhanced atomic layer deposition (ALD) process using the Ag(fod)(PEt3) precursor [(triethylphosphine)(6,6,7,7,8,8,8-heptafluoro-2,2-dimethy1-3,5-octanedionate)silver(I)] in combination with NH3-plasma is reported. The steady growth rate of the reported process (0.24 +/- 0.03 nm/cycle) was found to be 6 times larger than that of the previously reported Ag ALD process based on the same precursor in combination with H-2-plasma (0.04 +/- 0.02 nm/cycle). The ALD characteristics of the H-2-plasma and NH3-plasma processes were verified. The deposited Ag films were polycrystalline face-centered cubic Ag for both processes. The film morphology was investigated by ex situ scanning electron microscopy and grazing-incidence small-angle X-ray scattering, and it was found that films grown with the NH3-plasma process exhibit a much higher particle areal density and smaller particle sizes on oxide substrates compared to those deposited using the H-2-plasma process. This control over morphology of the deposited Ag is important for applications in catalysis and plasmonics. While films grown with the H-2-plasma process had oxygen impurities (similar to 9 atom %) in the bulk, the main impurity for the NH3-plasma process was nitrogen (similar to 7 atom %). In situ Fourier transform infrared spectroscopy experiments suggest that these nitrogen impurities are derived from NH surface groups generated during the NH3-plasma, which interact with the precursor molecules during the precursor pulse. We propose that the reaction of these surface groups with the precursor leads to additional deposition of Ag atoms during the precursor pulse compared to the H-2-plasma process, which explains the enhanced growth rate of the NH3-plasma process.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.466
Times cited: 9
DOI: 10.1021/ACS.CHEMMATER.7B00690
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“Cyclist exposure to black carbon, ultrafine particles and heavy metals : an experimental study along two commuting routes near Antwerp, Belgium”. Hofman J, Samson R, Joosen S, Blust R, Lenaerts S, Environmental research 164, 530 (2018). http://doi.org/10.1016/J.ENVRES.2018.03.004
Abstract: Urban environments typically exhibit large atmospheric pollution variation, in both space and time. In contrast to traditional monitoring networks suffering from a limited spatial coverage, mobile platforms enable personalized high-resolution monitoring, providing valuable insights into personal atmospheric pollution exposure, and the identification of potential pollution hotspots. This study evaluated personal cyclist exposure to UFPs, BC and heavy metals whilst commuting near Antwerp, Belgium, by performing mobile measurements with wearable black carbon (BC) and ultrafine particle (UFP) instruments. Loaded micro-aethalometer filterstrips were chemically analysed and the inhaled pollutant dose determined from the exhibited heart rate. Considerable spatial pollutant variation was observed along the travelled routes, with distinct contributions from spatial factors (e.g. traffic intersections, urban park and market) and temporary events. On average 300% higher BC, 20% higher UFP and changing elemental concentrations are observed along the road traffic route (RT), when compared to the bicycle highway route (BH). Although the overall background pollution determines a large portion of the experienced personal exposure (in this case 53% for BC and 40% for UFP), cyclists can influence their personal atmospheric pollution exposure, by selecting less exposed commuting routes. Our results, hereby, strengthen the body of evidence in favour of further policy investments in isolated bicycle infrastructure.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Times cited: 9
DOI: 10.1016/J.ENVRES.2018.03.004
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“Unraveling Structural Information of Turkevich Synthesized Plasmonic Gold-Silver Bimetallic Nanoparticles”. Blommaerts N, Vanrompay H, Nuti S, Lenaerts S, Bals S, Verbruggen SW, Small 15, 1902791 (2019). http://doi.org/10.1002/smll.201902791
Abstract: For the synthesis of gold-silver bimetallic nanoparticles, the Turkevich method has been the state-of-the-art method for several decades. It has been presumed that this procedure results in a homogeneous alloy, although this has been debatable for many years. In this work, it is shown that neither a full alloy, nor a perfect core-shell particle is formed but rather a core-shell-like particle with altering metal composition along the radial direction. In-depth wet-chemical experiments are performed in combination with advanced transmission electron microscopy, including EDX tomography, and Finite Element Method modeling to support the observations. From the electron tomography results, the core-shell structure could be clearly visualized and the spatial distribution of gold and silver atoms could be quantified. Theoretical simulations are performed to demonstrate that even though UV-Vis spectra show only one plasmon band, this still originates from core-shell type structures. The simulations also indicate that the core-shell morphology does not so much affect the location of the plasmon band, but mainly results in significant band broadening. Wet-chemistry experiments provide the evidence that the synthesis pathway starts with gold enriched alloy cores, and later on in the synthesis mainly silver is incorporated to end up with a silver enriched alloy shell.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 8.643
Times cited: 26
DOI: 10.1002/smll.201902791
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“Interfacial co-existence of oxygen and titanium vacancies in nanostructured TiO₂, for enhancement of carrier transport”. Lu Y, Liu Y-X, He L, Wang L-Y, Liu X-L, Liu J-W, Li Y-Z, Tian G, Zhao H, Yang X-H, Liu J, Janiak C, Lenaerts S, Yang X-Y, Su B-L, Nanoscale 12, 8364 (2020). http://doi.org/10.1039/D0NR01180K
Abstract: The interfacial co-existence of oxygen and metal vacancies in metal oxide semiconductors and their highly efficient carrier transport have rarely been reported. This work reports on the co-existence of oxygen and titanium vacancies at the interface between TiO2 and rGO via a simple two-step calcination treatment. Experimental measurements show that the oxygen and titanium vacancies are formed under 550 degrees C/Ar and 350 degrees C/air calcination conditions, respectively. These oxygen and titanium vacancies significantly enhance the transport of interfacial carriers, and thus greatly improve the photocurrent performances, the apparent quantum yield, and photocatalysis such as photocatalytic H-2 production from water-splitting, photocatalytic CO2 reduction and photo-electrochemical anticorrosion of metals. A new “interfacial co-existence of oxygen and titanium vacancies” phenomenon, and its characteristics and mechanism are proposed at the atomic-/nanoscale to clarify the generation of oxygen and titanium vacancies as well as the interfacial carrier transport.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.7
Times cited: 4
DOI: 10.1039/D0NR01180K
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“Influence of adding low concentration of oxygenates in mineral diesel oil and biodiesel on the concentration of NO, NO₂, and particulate matter in the exhaust gas of a one-cylinder diesel generator”. Maes RR, Potters G, Fransen E, Van Schaeren R, Lenaerts S, International journal of environmental research and public health 19, 7637 (2022). http://doi.org/10.3390/IJERPH19137637
Abstract: Air quality currently poses a major risk to human health worldwide. Transportation is one of the principal contributors to air pollution due to the quality of exhaust gases. For example, the widely used diesel fuel is a significant source of nitrogen oxides (NOx) and particulate matter (PM). To reduce the content NOx and PM, different oxygenated compounds were mixed into a mineral diesel available at the pump, and their effect on the composition of exhaust gas emissions was measured using a one-cylinder diesel generator. In this setup, adding methanol gave the best relative results. The addition of 2000 ppm of methanol decreased the content of NO by 56%, 2000 ppm of isopropanol decreased NO2 by 50%, and 2000 ppm ethanol decreased PM by 63%. An interesting question is whether it is possible to reduce the impact of hazardous components in the exhaust gas even more by adding oxygenates to biodiesels. In this article, alcohol is added to biodiesel in order to establish the impact on PM and NOx concentrations in the exhaust gases. Adding methanol, ethanol, and isopropanol at concentrations of 2000 ppm and 4000 ppm did not improve NOx emissions. The best results were using pure RME for a low NO content, pure diesel for a low NO2 content, and for PM there were no statistically significant differences.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.3390/IJERPH19137637
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“Can we find an optimal fatty acid composition of biodiesel in order to improve oxidation stability?”.Maes RR, Potters G, Fransen E, Geuens J, Van Schaeren R, Lenaerts S, Sustainability 15, 10310 (2023). http://doi.org/10.3390/SU151310310
Abstract: Air quality currently poses a major risk for human health. Currently, diesel is widely used as fuel and is a significant source of nitrogen oxides (NOx) and particulate matter (PM), both hazardous to human health. A good alternative for mineral diesel is biodiesel, not only for the improvement of hazardous components in the exhaust gases but also because it can be produced in view of a circular economy. Biodiesel consists of a mix of different fatty acid methyl esters, which can react with oxygen. As a consequence, the oxidation stability of biodiesel has to be studied, because the oxidation of biodiesel could affect the performance of the engine due to the wear of injectors and fuel pumps. The oxidation stability could also affect the quality of the exhaust gases due to increases in NOx and PM. The basic question we try to answer in this communication is: 'Can we find an optimal fatty acid composition in order to have a maximal oxidation stability?' In this article, we try to find the optimal fatty acid composition according to the five most common fatty acid methyl esters present in biodiesel in order to reach a maximal oxidation stability. The measurements and statistical analysis show, however, that there is no useful regression model because there are statistically significant two- and three-way interactions among the different fatty acids.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Medical Genetics (MEDGEN)
Impact Factor: 3.9
DOI: 10.3390/SU151310310
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“Hierarchical MoS2@TiO2 heterojunctions for enhanced photocatalytic performance and electrocatalytic hydrogen evolution”. Dong Y, Chen S-Y, Lu Y, Xiao Y-X, Hu J, Wu S-M, Deng Z, Tian G, Chang G-G, Li J, Lenaerts S, Janiak C, Yang X-Y, Su B-L, Chemistry: an Asian journal 13, 1609 (2018). http://doi.org/10.1002/ASIA.201800359
Abstract: Hierarchical MoS2@TiO2 heterojunctions were synthesized through a one-step hydrothermal method by using protonic titanate nanosheets as the precursor. The TiO2 nanosheets prevent the aggregation of MoS2 and promote the carrier transfer efficiency, and thus enhance the photocatalytic and electrocatalytic activity of the nanostructured MoS2. The obtained MoS2@TiO2 has significantly enhanced photocatalytic activity in the degradation of rhodamineB (over 5.2times compared with pure MoS2) and acetone (over 2.8times compared with pure MoS2). MoS2@TiO2 is also beneficial for electrocatalytic hydrogen evolution (26times compared with pure MoS2, based on the cathodic current density). This work offers a promising way to prevent the self-aggregation of MoS2 and provides a new insight for the design of heterojunctions for materials with lattice mismatches.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.083
Times cited: 22
DOI: 10.1002/ASIA.201800359
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“Light-induced processes in plasmonic Gold/TiO2 photocatalysts studied by electron paramagnetic resonance”. Caretti I, Keulemans M, Verbruggen SW, Lenaerts S, Van Doorslaer S, Topics in catalysis 58, 776 (2015). http://doi.org/10.1007/S11244-015-0419-4
Abstract: X-band and W-band continuous-wave (CW) electron paramagnetic resonance (EPR) was used to study in situ light-induced (LI) mechanisms in commercial P90 titania (90 % anatase/10 % rutile) compared to plasmon-enhanced Au-P90 photocatalyst. These materials were excited using UV and 532 nm visible light to generate different excitation states and distinguish pure charge separation from plasmon-assisted resonance processes. Up to nine different photoinduced species of trapped electrons and holes were identified. LI CW EPR of P90 is presented for the first time, showing a UV excitation response similar to the well-known mixed-phase P25 titania. It is shown that incorporation of Au nanoparticles in Au-P90 and formation of a Schottky junction affects the charge separation state of the catalyst under UV light. Moreover, Au impregnation activated P90 through plasmon hot electron injection under visible light excitation (plasmonic sensitization effect). In general, EPR proved to be crucial to determine the different photoexciation paths and reactions that regulate plasmonic photocatalysis.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.486
Times cited: 22
DOI: 10.1007/S11244-015-0419-4
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“Study of positive and negative plasma catalytic oxidation of ethylene”. Van Wesenbeeck K, Hauchecorne B, Lenaerts S, Environmental technology 38, 1554 (2017). http://doi.org/10.1080/09593330.2016.1237553
Abstract: The effect of introducing a photocatalytically active coating inside a plasma unit is investigated. This technique combines the advantages of high product selectivity from catalysis and the fast start-up from plasma technology. In this study, a preselected TiO2 coating is applied on the collector electrode of a DC corona discharge unit as non-thermal plasma reactor, in order to study the oxidation of ethylene. For both positive and negative polarities an enhanced mineralization is observed while the formation of by-products drastically decreases. The plasma catalytic unit gave the best results when using negative polarity at a voltage of 15kV. This shows the potential of plasma catalysis as indoor air purification technology.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.751
Times cited: 1
DOI: 10.1080/09593330.2016.1237553
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“Factors driving the activity of commercial titanium dioxide powders towards gas phase photocatalytic oxidation of acetaldehyde”. Verbruggen SW, Masschaele K, Moortgat E, Korany TE, Hauchecorne B, Martens JA, Lenaerts S, Catalysis science &, technology 2, 2311 (2012). http://doi.org/10.1039/C2CY20123B
Abstract: The photocatalytic activity of two commercial titanium dioxide powders (Cristal Global, Millennium PC500 and Evonik, P25) is compared towards acetaldehyde degradation in the gas phase. In contrast to the extensive literature available, we found a higher activity for the PC500 than for the P25 coating. Here, we present a comprehensive characterization of the bulk and surface properties of both powders. Our comparison shows that the material properties that dominate the overall photocatalytic activity in gas phase differ from those required for the photodegradation of water-borne pollutants.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.773
Times cited: 33
DOI: 10.1039/C2CY20123B
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“In situ study of ballast tank corrosion on ships: part 2”. Verstraelen H, de Baere K, Schillemans W, Lemmens L, Dewil R, Lenaerts S, Potters G, Materials performance 48, 54 (2009)
Abstract: A study was undertaken to determine causes and effects of corrosion processes in ballast tanks. Part 1 of this article (October 2009 MP) described the data collection. Part 2 describes the development of a corrosion index (CI) derived from the general International Association of Classification Societies corrosion assessment methods. The CI can be used in situ to assess ballast tank corrosion. An average timeline for-corrosion of tanks is presented.
Keywords: A1 Journal article; Engineering sciences. Technology; Theory of quantum systems and complex systems; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 0.149
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“Characterization of silver-polymer core–shell nanoparticles using electron microscopy”. Claes N, Asapu R, Blommaerts N, Verbruggen SW, Lenaerts S, Bals S, Nanoscale 10, 9186 (2018). http://doi.org/10.1039/C7NR09517A
Abstract: Silver-polymer core–shell nanoparticles show interesting optical properties, making them widely applicable in the field of plasmonics. The uniformity, thickness and homogeneity of the polymer shell will affect the properties of the system which makes a thorough structural characterization of these core–shell silver-polymer nanoparticles of great importance. However, visualizing the shell and the particle simultaneously is far from straightforward due to the sensitivity of the polymer shell towards the electron beam. In this study, we use different 2D and 3D electron microscopy techniques to investigate different structural aspects of the polymer coating.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.367
Times cited: 11
DOI: 10.1039/C7NR09517A
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“In situ study of ballast tank corrosion on ships: part 1”. Verstraelen H, de Baere K, Schillemans W, Lemmens L, Dewil R, Lenaerts S, Potters G, Materials performance 48, 48 (2009)
Keywords: A1 Journal article; Engineering sciences. Technology; Theory of quantum systems and complex systems; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 0.149
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“A non-aqueous synthesis of TiO2SiO2 composites in supercritical CO2 for the photodegradation of pollutants”. Jammaer J, Aprile C, Verbruggen SW, Lenaerts S, Pescarmona PP, Martens JA, Chemsuschem 4, 1457 (2011). http://doi.org/10.1002/CSSC.201100059
Abstract: Titania/silica composites with different Ti/Si ratios are synthesized via a nonconventional synthesis route. The synthesis involves non-aqueous reaction of metal alkoxides and formic acid at 75 °C in supercritical carbon dioxide. The as-prepared composite materials contain nanometer-sized anatase crystallites and amorphous silica. Large specific surface areas are obtained. The composites are evaluated in the photocatalytic degradation of phenol in aqueous medium, and in the elimination of acetaldehyde from air. The highest photocatalytic activity in both processes is achieved with a composite containing 40 wt % TiO2.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.226
Times cited: 15
DOI: 10.1002/CSSC.201100059
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“Layer-by-Layer-Stabilized Plasmonic Gold-Silver Nanoparticles on TiO2: Towards Stable Solar Active Photocatalysts”. Dingenen F, Blommaerts N, Van Hal M, Borah R, Arenas-Esteban D, Lenaerts S, Bals S, Verbruggen SW, Nanomaterials 11, 2624 (2021). http://doi.org/10.3390/nano11102624
Abstract: To broaden the activity window of TiO2, a broadband plasmonic photocatalyst has been designed and optimized. This plasmonic ‘rainbow’ photocatalyst consists of TiO2 modified with gold–silver composite nanoparticles of various sizes and compositions, thus inducing a broadband interaction with polychromatic solar light. However, these nanoparticles are inherently unstable, especially due to the use of silver. Hence, in this study the application of the layer-by-layer technique is introduced to create a protective polymer shell around the metal cores with a very high degree of control. Various TiO2 species (pure anatase, PC500, and P25) were loaded with different plasmonic metal loadings (0–2 wt %) in order to identify the most solar active composite materials. The prepared plasmonic photocatalysts were tested towards stearic acid degradation under simulated sunlight. From all materials tested, P25 + 2 wt % of plasmonic ‘rainbow’ nanoparticles proved to be the most promising (56% more efficient compared to pristine P25) and was also identified as the most cost-effective. Further, 2 wt % of layer-by-layer-stabilized ‘rainbow’ nanoparticles were loaded on P25. These layer-by-layer-stabilized metals showed superior stability under a heated oxidative atmosphere, as well as in a salt solution. Finally, the activity of the composite was almost completely retained after 1 month of aging, while the nonstabilized equivalent lost 34% of its initial activity. This work shows for the first time the synergetic application of a plasmonic ‘rainbow’ concept and the layer-by-layer stabilization technique, resulting in a promising solar active, and long-term stable photocatalyst.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.553
Times cited: 7
DOI: 10.3390/nano11102624
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