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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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“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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“Photocatalytic degradation of ethylene : an FTIR in situ study under atmospheric conditions”. Hauchecorne B, Tytgat T, Verbruggen SW, Hauchecorne D, Terrens D, Smits M, Vinken K, Lenaerts S, Applied catalysis : B : environmental 105, 111 (2011). http://doi.org/10.1016/J.APCATB.2011.03.041
Abstract: In this paper, the reaction mechanism of the photocatalytic oxidation of ethylene is elucidated by means of an in-house developed FTIR in situ reactor. This reactor allowed us to look at the catalytic surface at the moment the reactions actually occur. This new approach gave some exciting new insights in how ethylene is photocatalytically oxidised. It was found that there is a change in dipole moment of the ethylene molecule when it is brought in the neighbourhood of the catalyst. From this finding, a hypothesis was formulated on how the CC-bond from ethylene will break. It was found that the aforementioned interaction between the catalyst and the molecule, allows the excited electrons from the UV irradiated catalyst to occupy the lowest unoccupied molecular orbital (LUMO) of the ethylene molecule through a process known as backdonation. Following this hypothesis, it was found that the degradation occurs through the formation of two intermediates: formaldehyde and formic acid, for which formaldehyde is bound in two different ways (coordinatively and as bidentate). Finally CO2 and H2O are found as end products, resulting in the complete mineralisation of the pollutant.
Keywords: A1 Journal article; Engineering sciences. Technology; Molecular Spectroscopy (MolSpec); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 29
DOI: 10.1016/J.APCATB.2011.03.041
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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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“Predicting the surface plasmon resonance wavelength of gold-silver alloy nanoparticles”. Verbruggen SW, Keulemans M, Martens JA, Lenaerts S, The journal of physical chemistry: C : nanomaterials and interfaces 117, 19142 (2013). http://doi.org/10.1021/JP4070856
Abstract: Gold-silver alloy nanoparticles display surface plasmon resonance (SPR) over a broad range of the UV-vis spectrum. We propose a model to predict the SPR wavelength of gold-silver alloy colloids based on the combined effect of alloy composition and particle size. The SPR wavelength is derived from extinction spectra simulated using available experimental dielectric constant data and accounts for particle size by applying Mie theory. Comparison of calculated values with experimental data evidences the accuracy of the model. The new SPR wavelength estimation tool will be of particular interest for developing dedicated bimetallic plasmonic nanostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.536
Times cited: 51
DOI: 10.1021/JP4070856
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“Surface photovoltage measurements : a quick assessment of the photocatalytic activity?”.Verbruggen SW, Dirckx JJJ, Martens JA, Lenaerts S, Catalysis today 209, 215 (2013). http://doi.org/10.1016/J.CATTOD.2012.11.010
Abstract: Surface photovoltage (SPV) measurements can contribute to a better understanding of electronic properties of photocatalysts under illumination. Direct linking of SPV data to the actual photocatalytic activity remains troublesome. This work aims to discuss SPV measurements from a photocatalytic point of view. By means of several application-based scenarios we illustrate that the trend between SPV and photocatalysis strongly depends on parameters such as the crystal structure, surface modifications, morphology and humidity. This makes the interpretation far from straightforward.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.636
Times cited: 8
DOI: 10.1016/J.CATTOD.2012.11.010
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“TiO2 photocatalysis for the degradation of pollutants in gas phase : from morphological design to plasmonic enhancement”. Verbruggen SW, Journal of photochemistry and photobiology: C: photochemistry reviews 24, 64 (2015). http://doi.org/10.1016/J.JPHOTOCHEMREV.2015.07.001
Abstract: TiO2-based photocatalysis has become a viable technology in various application fields such as (waste)water purification, photovoltaics/artificial photosynthesis, environmentally friendly organic synthesis and remediation of air pollution. Because of the increasing impact of bad air quality worldwide, this review focuses on the use and optimization of TiO2-based photocatalysts for gas phase applications. Over the past years various specific aspects of TiO2 photocatalysis have been reviewed individually. The intent of this review is to offer a broad tutorial on (recent) trends in TiO2 photocatalyst modification for the intensification of photocatalytic air treatment. After briefly introducing the fundamentals of photocatalysis, TiO2 photocatalyst modification is discussed both on a morphological and an electronic level from the perspective of gas phase applications. The main focus is laid on recent developments, but also possible opportunities to the field. This review is intended as a solid introduction for researchers new to the field, as well as a summarizing update for established investigators. (C) 2015 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 12.317
Times cited: 121
DOI: 10.1016/J.JPHOTOCHEMREV.2015.07.001
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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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“Cost-effectiveness analysis to assess commercial TiO2 photocatalysts for acetaldehyde degradation in air”. Verbruggen SW, Tytgat T, Van Passel S, Martens JA, Lenaerts S, Chemicke zvesti 68, 1273 (2014). http://doi.org/10.2478/S11696-014-0557-3
Abstract: In the commercialisation of photocatalytic air purifiers, the performance as well as the cost of the catalytic material plays an important role. Where most comparative studies only regard the photocatalytic activity as a decisive parameter, in this study both activity and cost are taken into account. Using a cost-effectiveness analysis, six different commercially available TiO2-based catalysts are evaluated in terms of their activities in photocatalytic degradation of acetaldehyde as a model reaction for indoor air purification.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.258
Times cited: 10
DOI: 10.2478/S11696-014-0557-3
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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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“Coupling of phthalocyanines with plasmonic gold nanoparticles by click chemistry for an enhanced singlet oxygen based photoelectrochemical sensing”. Khan SU, Matshitse R, Borah R, Nemakal M, Moiseeva EO, Dubinina TV, Nyokong T, Verbruggen SW, De Wael K, ChemElectroChem , 1 (2024). http://doi.org/10.1002/CELC.202300677
Abstract: Coupling photosensitizers (PSs) with plasmonic nanoparticles increases the photocatalytic activity of PSs as the localized surface plasmon resonance (LSPR) of plasmonic nanoparticles leads to extreme concentration of light in their vicinity known as the near-field enhancement effect. To realize this in a colloidal phase, efficient conjugation of the PS molecules with the plasmonic nanoparticle surface is critical. In this work, we demonstrate the coupling of phthalocyanine (Pc) molecules with gold nanoparticles (AuNPs) in the colloidal phase via click chemistry. This conjugated Pc-AuNPs colloidal system is shown to enhance the photocatalytic singlet oxygen (1O2) production over non-conjugated Pcs and hence improve the photoelectrochemical detection of phenols. The plasmonic enhancement of the 1O2 generation by Pcs was clearly elucidated by complementary experimental and computational classical electromagnetic models. The dependence of plasmonic enhancement on the spectral position of the excitation laser wavelength and the absorbance of the Pc molecules with respect to the wavelength specific near-field enhancement is clearly demonstrated. A high similar to 8 times enhancement is obtained with green laser (532 nm) at the LSPR due to the maximum near-field enhancement at the resonance wavelength. Zinc phthalocyanine is covalently linked to plasmonic AuNPs via click chemistry to investigate the synergistic effect that boosts the overall activity toward the detection of HQ under visible light illumination. The 1O2 quantum yield of ZnPc improved significantly after conjugating with AuNPs, resulting in enhanced photoelectrochemical activity. image
Keywords: A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Impact Factor: 4
DOI: 10.1002/CELC.202300677
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“Recent advances in metal-doped defective TiO₂, for photocatalytic CO₂, conversion”. Raes A, Minja AC, Ag KR, Verbruggen SW, Current Opinion in Chemical Engineering 44, 101013 (2024). http://doi.org/10.1016/J.COCHE.2024.101013
Abstract: Introducing defects in TiO2-based photocatalytic materials is a promising strategy for improving light-driven CO2 reduction. However, defects such as oxygen vacancies are generally unstable. As a solution and to further enhance the photocatalytic activity, metal doping has been applied. This mini review aims to summarize recent progress in this particular field. Herein, we have classified metal-doped architectures into three different categories: single metal doping, alloy- and co-doping, and doping of morphologically nanoengineered TiO2−x substrates. The direct relationship between specific metals and product selectivity remains complex, as selectivity can vary significantly among seemingly similar materials. However, numerous methods do show promise in fine-tuning selectivity towards either CO or CH4. In terms of photocatalytic turnover, remarkable yields have been reported in isolated reports, but insufficient experimental data and divergent reaction conditions hamper a true comparison. This puts an emphasis on the need for standardized activity testing.
Keywords: A1 Journal article; Engineering sciences. Technology
Impact Factor: 6.6
DOI: 10.1016/J.COCHE.2024.101013
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“Surface modification of mesostructured cellular foam to enhance hydrogen storage in binary THF/H₂, clathrate hydrate”. Kummamuru NB, Ciocarlan R-G, Houlleberghs M, Martens J, Breynaert E, Verbruggen SW, Cool P, Perreault P, Sustainable energy &, fuels , 1 (2024). http://doi.org/10.1039/D4SE00114A
Abstract: This study introduces solid-state tuning of a mesostructured cellular foam (MCF) to enhance hydrogen (H-2) storage in clathrate hydrates. Grafting of promoter-like molecules (e.g., tetrahydrofuran) at the internal surface of the MCF resulted in a substantial improvement in the kinetics of formation of binary H-2-THF clathrate hydrate. Identification of the confined hydrate as sII clathrate hydrate and enclathration of H-2 in its small cages was performed using XRD and high-pressure H-1 NMR spectroscopy respectively. Experimental findings show that modified MCF materials exhibit a similar to 1.3 times higher H-2 storage capacity as compared to non-modified MCF under the same conditions (7 MPa, 265 K, 100% pore volume saturation with a 5.56 mol% THF solution). The enhancement in H-2 storage is attributed to the hydrophobicity originating from grafting organic molecules onto pristine MCF, thereby influencing water interactions and fostering an environment conducive to H-2 enclathration. Gas uptake curves indicate an optimal tuning point for higher H-2 storage, favoring a lower density of carbon per nm(2). Furthermore, a direct correlation emerges between higher driving forces and increased H-2 storage capacity, culminating at 0.52 wt% (46.77 mmoles of H-2 per mole of H2O and 39.78% water-to-hydrate conversions) at 262 K for the modified MCF material with fewer carbons per nm(2). Notably, the substantial H-2 storage capacity achieved without energy-intensive processes underscores solid-state tuning's potential for H-2 storage in the synthesized hydrates. This study evaluated two distinct kinetic models to describe hydrate growth in MCF. The multistage kinetic model showed better predictive capabilities for experimental data and maintained a low average absolute deviation. This research provides valuable insights into augmenting H-2 storage capabilities and holds promising implications for future advancements.
Keywords: A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA)
DOI: 10.1039/D4SE00114A
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