TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocata...TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocatalysts. The structural features of the catalysts were characterized by X-ray di raction, transmission electron microscopy, inductively cou-pled plasma atomic emission spectrum, and H2 Temperature-programmed reduction. The photocatalytic property was studied by the O2 evolution from water oxidation, which was examined with respect to the in uences of Ru contents as well as the oxidation and reduction treatments, suggesting the charge separation effect of the Ru species co-catalysts on di erent facets of TiO2 nanosheets. In contrast to Ru/TiO2 and RuO2/TiO2 with the single deposited co-catalyst, the optimized catalyst 0.5%Ru-1.0%RuO2/TiO2 with dual co-catalysts achieved a much improved catalytic performance, in terms of the synergetic effect of dual co-catalysts and the enhanced charge separation effect.展开更多
Heterogeneous gold nanocatalysts have both inspired researchers with their unique catalytic performance and frustrated them due to the contradictions observed in their activities and stabilities.A recent breakthrough ...Heterogeneous gold nanocatalysts have both inspired researchers with their unique catalytic performance and frustrated them due to the contradictions observed in their activities and stabilities.A recent breakthrough has shown that gold nanoparticles(NPs)can retain their catalytically active size over a MgGa2O4 spinel support upon sintering at high temperatures.Herein,we report the catalytic activity of anti-sintering AuGMgGa2O4 for use in water gas shift reaction(WGSR)and catalytic combustion reactions,and the promoting effect of ceria.Upon adding ceria to 800℃-aged AuGMgGa2O4,the CO conversion in the WGSR was increased from ~1.5% to ~34.0% at 450 ℃,and the “light-off” temperatures(T50)for methane combustion and CO oxidation were decreased by ~80 and ~100 ℃,respectively.Characterizations using XRD,HAADF-STEM,EDS mapping,H2-TPR,XPS,and DRIFTs confirmed the proximate contact of Au with ceria and their significant synergistic effect,which thereby combined the benefits of ceria toward the dissociation of H2O or O2 and the Au NPs toward activating CO or CH4.These results show that this stepwise stabilization-activation strategy is efficient for rationally constructing stable and active gold nanocatalysts,which may open up possibilities for the wide application of gold nanocatalysts at elevated temperatures.展开更多
文摘TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocatalysts. The structural features of the catalysts were characterized by X-ray di raction, transmission electron microscopy, inductively cou-pled plasma atomic emission spectrum, and H2 Temperature-programmed reduction. The photocatalytic property was studied by the O2 evolution from water oxidation, which was examined with respect to the in uences of Ru contents as well as the oxidation and reduction treatments, suggesting the charge separation effect of the Ru species co-catalysts on di erent facets of TiO2 nanosheets. In contrast to Ru/TiO2 and RuO2/TiO2 with the single deposited co-catalyst, the optimized catalyst 0.5%Ru-1.0%RuO2/TiO2 with dual co-catalysts achieved a much improved catalytic performance, in terms of the synergetic effect of dual co-catalysts and the enhanced charge separation effect.
基金supported by the National Key R&D Program of China(2016YFA0202801)the National Natural Science Foundation of China(21403213,21673226)+1 种基金the"Transformational Technologies for Clean Energy and Demonstration"Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21040200)the "Hundred Talents Programme" of the Chinese Academy of Sciences~~
文摘Heterogeneous gold nanocatalysts have both inspired researchers with their unique catalytic performance and frustrated them due to the contradictions observed in their activities and stabilities.A recent breakthrough has shown that gold nanoparticles(NPs)can retain their catalytically active size over a MgGa2O4 spinel support upon sintering at high temperatures.Herein,we report the catalytic activity of anti-sintering AuGMgGa2O4 for use in water gas shift reaction(WGSR)and catalytic combustion reactions,and the promoting effect of ceria.Upon adding ceria to 800℃-aged AuGMgGa2O4,the CO conversion in the WGSR was increased from ~1.5% to ~34.0% at 450 ℃,and the “light-off” temperatures(T50)for methane combustion and CO oxidation were decreased by ~80 and ~100 ℃,respectively.Characterizations using XRD,HAADF-STEM,EDS mapping,H2-TPR,XPS,and DRIFTs confirmed the proximate contact of Au with ceria and their significant synergistic effect,which thereby combined the benefits of ceria toward the dissociation of H2O or O2 and the Au NPs toward activating CO or CH4.These results show that this stepwise stabilization-activation strategy is efficient for rationally constructing stable and active gold nanocatalysts,which may open up possibilities for the wide application of gold nanocatalysts at elevated temperatures.
