Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermo... more Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermore, it is recognized as possible future energy carrier achieving safe operation, storage and transportation. The...
Paper published as part of the special topic on Materials for Renewable Fuels Production ARTICLES... more Paper published as part of the special topic on Materials for Renewable Fuels Production ARTICLES YOU MAY BE INTERESTED IN Fast electron and slow hole spin relaxation in CsPbI 3 nanocrystals
Progress in Photovoltaics: Research and Applications, 2022
By reducing the thickness of the absorber layers, ultrathin GaAs solar cells can be fabricated in... more By reducing the thickness of the absorber layers, ultrathin GaAs solar cells can be fabricated in a more cost‐effective manner using less source material and shorter deposition times. In this work, ultrathin GaAs solar cells are presented with a diffuse scattering layer based on wide bandgap GaP grown directly on the device layers of the cells with MOCVD. The roughness and surface morphology are quantified using atomic force microscopy and the resulting diffuse scattering capability is assessed using wavelength‐dependent reflectance measurements. Ohmic rear contacts are made using contact points etched through the GaP layer, for which an etching procedure using I2:KI was developed and optimized. The performance of the GaP textured ultrathin GaAs cells are compared with equivalent planar cells using current density‐voltage measurements and external quantum efficiency measurements, where the GaP textured cells demonstrate an increase of 6.7% in the short‐circuit current density (JSC), which was found to be as high as 21.9 mA·cm−2 as a result of increased photon absorption by light‐trapping.
Employing methane as a C1 feedstock for commodity chemicals represents a sustainable and empoweri... more Employing methane as a C1 feedstock for commodity chemicals represents a sustainable and empowering opportunity for chemical catalysis. However, practical demands of industrial development have imposed serve challenges to utilize co-effective catalysts and reagents as well as ecologically benign conditions for highly efficient and selective C(sp3)–H bond functionalizations, constantly driving the development of catalytic strategies. The aerobic oxidative carbonylation of methane represents an ideal approach for sustainable acetic acid synthesis, yet poses a longstanding challenge in selectivity for C2:C1 products. In recent years, metallaphotocatalysis in which photoredox catalysts operate in synergy with transition metal catalysts to facilitate both 1- and 2-electron reaction steps, has provided intriguing opportunities to achieve selective cross-couplings otherwise unattainable. Here, we demonstrate the utilization of an iron terpyridine catalyst to facilitate multiple 1- and 2-el...
We have evaluated the applicability of Ni anodes in electrochemical conversion of H 2 S to form s... more We have evaluated the applicability of Ni anodes in electrochemical conversion of H 2 S to form sulfur (polysulfides) and H 2. Two different electrolytes containing sulfide were evaluated: a buffered solution of Na 2 HPO 4 at pH 9.2, and a NaOH solution at pH 13. At pH 9.2, deposition of sulfur on the Ni anode was observed, resulting in a significant decrease in electrochemical performance. The composition, morphology, and thickness of the sulfur deposit, as determined by Raman spectroscopy and SEM, was found to strongly depend on the applied potential, and ranged from dense S 8 films to highly porous spherical sulfur structures. Oxidation of the anode was also observed by conversion of Ni to NiS 2. The formation of the sulfur film was prevented by performing the reaction at pH 13 in NaOH in the range of − 1.0 V to + 0.6 V versus Hg/HgO. It is proposed that at these highly basic pH values, sulfur is dissolved in the electrolyte in the form of polysulfides, such as S 2 2− or S 8 2−. When using Ni anodes some oxygen evolution was observed at the anode, in particular at pH 13, resulting in a Faradaic efficiency for sulfur removal of ~ 90%.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2019
DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Reduction of CO2 to CO for sustainable fuel production is studied in high-temperature (&gt;35... more Reduction of CO2 to CO for sustainable fuel production is studied in high-temperature (&gt;3500 K) microwave plasma. Raman scattering and chemical kinetics modeling reveal chemistry rates with spatial resolution that explain previously reported peak energy efficiency values of 50%. The necessary product quenching is established by fast transport in the core, at frequencies of 105 s–1, facilitating rapid mass and energy transfer between products and feedstock CO2. Moreover, the resulting chemical nonequilibrium yields additional CO2 dissociation in O–CO2 association, a reaction responsible for up to 45% of CO production. Three different thermal chemistry sets are invoked to qualitatively confirm this picture. It is shown how these lack predictive accuracy in the high gas temperature regime studied, which indicates that new CO2 chemistry rate coefficients are highly desirable. Improving reactor design with the identified enhancement mechanisms in mind can increase efficiency up to the newly defined thermal limit of 70%.</p
Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermo... more Hydrogen peroxide (H2O2) is a valuable green oxidant with a wide range of applications. Furthermore, it is recognized as possible future energy carrier achieving safe operation, storage and transportation. The...
Paper published as part of the special topic on Materials for Renewable Fuels Production ARTICLES... more Paper published as part of the special topic on Materials for Renewable Fuels Production ARTICLES YOU MAY BE INTERESTED IN Fast electron and slow hole spin relaxation in CsPbI 3 nanocrystals
Progress in Photovoltaics: Research and Applications, 2022
By reducing the thickness of the absorber layers, ultrathin GaAs solar cells can be fabricated in... more By reducing the thickness of the absorber layers, ultrathin GaAs solar cells can be fabricated in a more cost‐effective manner using less source material and shorter deposition times. In this work, ultrathin GaAs solar cells are presented with a diffuse scattering layer based on wide bandgap GaP grown directly on the device layers of the cells with MOCVD. The roughness and surface morphology are quantified using atomic force microscopy and the resulting diffuse scattering capability is assessed using wavelength‐dependent reflectance measurements. Ohmic rear contacts are made using contact points etched through the GaP layer, for which an etching procedure using I2:KI was developed and optimized. The performance of the GaP textured ultrathin GaAs cells are compared with equivalent planar cells using current density‐voltage measurements and external quantum efficiency measurements, where the GaP textured cells demonstrate an increase of 6.7% in the short‐circuit current density (JSC), which was found to be as high as 21.9 mA·cm−2 as a result of increased photon absorption by light‐trapping.
Employing methane as a C1 feedstock for commodity chemicals represents a sustainable and empoweri... more Employing methane as a C1 feedstock for commodity chemicals represents a sustainable and empowering opportunity for chemical catalysis. However, practical demands of industrial development have imposed serve challenges to utilize co-effective catalysts and reagents as well as ecologically benign conditions for highly efficient and selective C(sp3)–H bond functionalizations, constantly driving the development of catalytic strategies. The aerobic oxidative carbonylation of methane represents an ideal approach for sustainable acetic acid synthesis, yet poses a longstanding challenge in selectivity for C2:C1 products. In recent years, metallaphotocatalysis in which photoredox catalysts operate in synergy with transition metal catalysts to facilitate both 1- and 2-electron reaction steps, has provided intriguing opportunities to achieve selective cross-couplings otherwise unattainable. Here, we demonstrate the utilization of an iron terpyridine catalyst to facilitate multiple 1- and 2-el...
We have evaluated the applicability of Ni anodes in electrochemical conversion of H 2 S to form s... more We have evaluated the applicability of Ni anodes in electrochemical conversion of H 2 S to form sulfur (polysulfides) and H 2. Two different electrolytes containing sulfide were evaluated: a buffered solution of Na 2 HPO 4 at pH 9.2, and a NaOH solution at pH 13. At pH 9.2, deposition of sulfur on the Ni anode was observed, resulting in a significant decrease in electrochemical performance. The composition, morphology, and thickness of the sulfur deposit, as determined by Raman spectroscopy and SEM, was found to strongly depend on the applied potential, and ranged from dense S 8 films to highly porous spherical sulfur structures. Oxidation of the anode was also observed by conversion of Ni to NiS 2. The formation of the sulfur film was prevented by performing the reaction at pH 13 in NaOH in the range of − 1.0 V to + 0.6 V versus Hg/HgO. It is proposed that at these highly basic pH values, sulfur is dissolved in the electrolyte in the form of polysulfides, such as S 2 2− or S 8 2−. When using Ni anodes some oxygen evolution was observed at the anode, in particular at pH 13, resulting in a Faradaic efficiency for sulfur removal of ~ 90%.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2019
DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Reduction of CO2 to CO for sustainable fuel production is studied in high-temperature (&gt;35... more Reduction of CO2 to CO for sustainable fuel production is studied in high-temperature (&gt;3500 K) microwave plasma. Raman scattering and chemical kinetics modeling reveal chemistry rates with spatial resolution that explain previously reported peak energy efficiency values of 50%. The necessary product quenching is established by fast transport in the core, at frequencies of 105 s–1, facilitating rapid mass and energy transfer between products and feedstock CO2. Moreover, the resulting chemical nonequilibrium yields additional CO2 dissociation in O–CO2 association, a reaction responsible for up to 45% of CO production. Three different thermal chemistry sets are invoked to qualitatively confirm this picture. It is shown how these lack predictive accuracy in the high gas temperature regime studied, which indicates that new CO2 chemistry rate coefficients are highly desirable. Improving reactor design with the identified enhancement mechanisms in mind can increase efficiency up to the newly defined thermal limit of 70%.</p
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Papers by Joost Smits