Nanostructured titanium dioxides were synthesized via various post-treatments of titanate nanofibers obtained from titanium precursors by hydrothermal reactions. The microstructures of TiO2 and supported Ru/TiO2 catal...Nanostructured titanium dioxides were synthesized via various post-treatments of titanate nanofibers obtained from titanium precursors by hydrothermal reactions. The microstructures of TiO2 and supported Ru/TiO2 catalysts were characterized with X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, and nitrogen adsorption isotherms. The phase structure, particle size, morphology, and specific surface area were determined. The supported Ru catalysts were applied for the selective methanation of CO in a hydrogen-rich stream. The results indicated that the Ru catalyst supported on rutile and TiO2-B exhibited higher catalytic performance than the counterpart supported on anatase, which suggested the distinct interaction between Ru nanoparticles and TiO2 resulting from different crystalline phases and morphology.展开更多
Multi-walled carbon nanotubes （MWCNT） supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop-erties of the catalysts were characterized...Multi-walled carbon nanotubes （MWCNT） supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop-erties of the catalysts were characterized by XRD, TEM, H2-TPR, XPS and Raman spectra, indicating the strong interactions between Cu and Co mixed oxides as well as between metal oxides and MWCNT support. The catalytic performance of CO removal in a H2-rich stream was examined. In contrast to the single Cu and Co catalyst, the unique performance was ob-served for Cu-Co composite catalysts, which features an unusual reaction pathway through the combination of CO preferential oxidation and CO methanation especially at high reac-tion temperature. The optimal catalyst with Cu/Co ratio of 1/8 can achieve the complete CO conversion in a wider temperature range of 150-250 ℃ under the space velocity as high as 120 L/（h·g）, which demonstrates a promising catalyst for the e ective CO removal in a H2-rich stream.展开更多
Elucidation of the CuOx-CeO2 interactions is of great interest and importance in understanding complex CuOx-CeO2 interfacial catalysis in various reactions. In the present work, we have investigated structures and cat...Elucidation of the CuOx-CeO2 interactions is of great interest and importance in understanding complex CuOx-CeO2 interfacial catalysis in various reactions. In the present work, we have investigated structures and catalytic activity in CO oxidation of CuOx species on CeO2 rods, cubes and polyhedra predominantly exposing {110}+{100}, {100} and {111} facets by the incipient wetness impregnation method with the lowest Cu loading of 0.025%. The structural evolution of CuOx species was found to depend on both the Cu loading and the CeO2 morphology. As the Cu loading increases, CuOx species are deposited preferentially on the surface defect of CeO2 and then aggregate and grow, accompanied by the formation of isolated Cu ions, CuOx clusters strongly/weakly interacting with the CeO2, highly dispersed Cu O nanoparticles, and large Cu O nanoparticles. The isolated Cu^+ species and CuOx clusters weakly interacting with the CeO2 were observed mainly on the O-terminated CeO2{100} facets. Meanwhile, more Cu(I) species are stabilized during CO reduction processes in CuOx/c-CeO2 catalysts than in CuOx/r-CeO2 and CuOx/p-CeO2 catalysts. The catalytic activities of various CuOx/CeO2 catalysts in CO oxidation vary with both the CuOx species and the CeO2 morphology. These results comprehensively elucidate the CuOx-CeO2 interactions and exemplify their morphology-dependence.展开更多
基金V. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20703042）, the National Basic Research Program of China （No.2010 CB923300）, USTC-NSRL Association Funding （No.KY 2060030009）, and Fundamental Research Funds for the Central Universities （No.WK2060030010）.
文摘Nanostructured titanium dioxides were synthesized via various post-treatments of titanate nanofibers obtained from titanium precursors by hydrothermal reactions. The microstructures of TiO2 and supported Ru/TiO2 catalysts were characterized with X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, and nitrogen adsorption isotherms. The phase structure, particle size, morphology, and specific surface area were determined. The supported Ru catalysts were applied for the selective methanation of CO in a hydrogen-rich stream. The results indicated that the Ru catalyst supported on rutile and TiO2-B exhibited higher catalytic performance than the counterpart supported on anatase, which suggested the distinct interaction between Ru nanoparticles and TiO2 resulting from different crystalline phases and morphology.
文摘Multi-walled carbon nanotubes （MWCNT） supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop-erties of the catalysts were characterized by XRD, TEM, H2-TPR, XPS and Raman spectra, indicating the strong interactions between Cu and Co mixed oxides as well as between metal oxides and MWCNT support. The catalytic performance of CO removal in a H2-rich stream was examined. In contrast to the single Cu and Co catalyst, the unique performance was ob-served for Cu-Co composite catalysts, which features an unusual reaction pathway through the combination of CO preferential oxidation and CO methanation especially at high reac-tion temperature. The optimal catalyst with Cu/Co ratio of 1/8 can achieve the complete CO conversion in a wider temperature range of 150-250 ℃ under the space velocity as high as 120 L/（h·g）, which demonstrates a promising catalyst for the e ective CO removal in a H2-rich stream.
文摘Elucidation of the CuOx-CeO2 interactions is of great interest and importance in understanding complex CuOx-CeO2 interfacial catalysis in various reactions. In the present work, we have investigated structures and catalytic activity in CO oxidation of CuOx species on CeO2 rods, cubes and polyhedra predominantly exposing {110}+{100}, {100} and {111} facets by the incipient wetness impregnation method with the lowest Cu loading of 0.025%. The structural evolution of CuOx species was found to depend on both the Cu loading and the CeO2 morphology. As the Cu loading increases, CuOx species are deposited preferentially on the surface defect of CeO2 and then aggregate and grow, accompanied by the formation of isolated Cu ions, CuOx clusters strongly/weakly interacting with the CeO2, highly dispersed Cu O nanoparticles, and large Cu O nanoparticles. The isolated Cu^+ species and CuOx clusters weakly interacting with the CeO2 were observed mainly on the O-terminated CeO2{100} facets. Meanwhile, more Cu(I) species are stabilized during CO reduction processes in CuOx/c-CeO2 catalysts than in CuOx/r-CeO2 and CuOx/p-CeO2 catalysts. The catalytic activities of various CuOx/CeO2 catalysts in CO oxidation vary with both the CuOx species and the CeO2 morphology. These results comprehensively elucidate the CuOx-CeO2 interactions and exemplify their morphology-dependence.
