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Item type:Publication, Access status: with files , 2D photonic crystal emitter at 1,400°C for thermophotovoltaic energy harvesting(Elsevier, 2025-10-15); ; ; ; Spectrally selective emitters that endure extreme temperatures (exceeding 1,000°C) are vital for thermophotovoltaic energy harvesting. Here, we report a 2D photonic crystal emitter composed of yttria-stabilized zirconia particles on a tungsten mirror, fabricated through a simple and scalable self-assembly process. The emitter demonstrates spectral stability for 2 h and structural stability for 14 h at 1,400°C under high vacuum, with degradation attributed to zirconium nitridation, which is avoided under Ar or forming gas atmospheres. Long-term durability is demonstrated over 6 months and 200 thermal cycles at 1,050°C, effectively mitigating tungsten oxidation. The emitter achieves 52% spectral efficiency for a 0.72 eV photovoltaic band gap. This work offers perspectives on designing and implementing spectrally selective emitters that remain stable at high temperatures and resilient in harsh environments, representing a significant step forward in developing robust thermophotovoltaic energy-harvesting systems.Publicationtype: Journal Article21 22 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Spatially resolved reaction profiles of CO2 hydrogenation to methanol using in-based catalysts in a compact profile reactor(American Chemical Society (ACS), 2024-06-07); ; ; ; The compact profile reactor (CPR) design allows for the simultaneous acquisition of species, temperature, and spatially resolved reaction profiles during high-pressure CO2 hydrogenation to methanol. Indium-based catalysts for CO2 hydrogenation have attracted significant scientific interest since they are more selective, efficient, and resistant to deactivation compared to the state-of-the-art copper-based catalyst. In this study, the reaction profile of In2O3/ZrO2 catalysts is compared to that of the state-of-the-art Cu/ZnO/Al2O3 (CZA) catalyst in a high-pressure CPR. It is demonstrated that the addition of nickel as a promoter significantly enhanced the catalytic activity of pure In2O3/ZrO2. The characterization by H2 TPR and CO2 TPD revealed an increased capacity for both hydrogen and CO2. A detailed comparison and optimization of reaction conditions using Ni–In2O3/ZrO2 as a catalyst are presented. In an optimized experiment, Ni–In2O3/ZrO2 produces 4.90 gMeOH gIn+Ni–1 h–1 at 275 °C, 50 bar, and 63,000 h–1with a methanol selectivity of 73%. Furthermore, no catalyst deactivation caused by metal leaching or sintering could be observed over 90 h time on stream.Publicationtype: Journal Article209 125 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Synthesis and thermal stability of ZrO2@SiO2 core-shell submicron particles(Royal Society of Chemistry (RSC), 2019-08-28); ; ; ; ZrO2@SiO2 core-shell submicron particles are promising candidates for the development of advanced optical materials. Here, submicron zirconia particles were synthesized using a modified sol-gel method and pre-calcined at 400 °C. Silica shells were grown on these particles (average size: ∼270 nm) with well-defined thicknesses (26 to 61 nm) using a seeded-growth Stöber approach. To study the thermal stability of bare ZrO2 cores and ZrO2@SiO2 core-shell particles they were calcined at 450 to 1200 °C. After heat treatments, the particles were characterized by SEM, TEM, STEM, cross-sectional EDX mapping, and XRD. The non-encapsulated, bare ZrO2 particles predominantly transitioned to the tetragonal phase after pre-calcination at 400 °C. Increasing the temperature to 600 °C transformed them to monoclinic. Finally, grain coarsening destroyed the spheroidal particle shape after heating to 800 °C. In striking contrast, SiO2-encapsulation significantly inhibited grain growth and the t → m transition progressed considerably only after heating to 1000 °C, whereupon the particle shape, with a smooth silica shell, remained stable. Particle disintegration was observed after heating to 1200 °C. Thus, ZrO2@SiO2 core-shell particles are suited for high-temperature applications up to ∼1000 °C. Different mechanisms are considered to explain the markedly enhanced stability of ZrO2@SiO2 core-shell particles.Publicationtype: Journal ArticleScopus© Citations 14 278 352