The supported Au/TiO2 and Au/TiO2-SiO2 catalysts were prepared by deposition precipitation method. The TPD study reveals that propylene oxide competes with propylene to be adsorbed on the same adsorptive center-Ti^n＋...The supported Au/TiO2 and Au/TiO2-SiO2 catalysts were prepared by deposition precipitation method. The TPD study reveals that propylene oxide competes with propylene to be adsorbed on the same adsorptive center-Ti^n＋ site on the surface of the catalyst and that the adisorbing capacity of the catalyst for propylene oxide is larger than that for propylene. Catalytic behavior for propylene epoxidation with H2 and O2 was tested in a micro-reactor. Under typical conditions, the selectivity for propylene oxide is over 87%. The TG curves show that PO successive oxidation cause carbon deposition on the active center and deactivation of the Au catalysts. Because the amounts of Tin＋ site decrease significantly, and consequently the separation between Ti^n＋ sites increases, the Au/TiO2-SiO2 catalyst is more stable than Au/TiO2.展开更多
The objective of the paper is to report results on fabrication, structural, morphological and performance characteristics of novel TiO2/PS/Si, Au/TiO2/PS/Si and Au/PS/Si direct ammonia fuel cells (DAFC) using nanoporo...The objective of the paper is to report results on fabrication, structural, morphological and performance characteristics of novel TiO2/PS/Si, Au/TiO2/PS/Si and Au/PS/Si direct ammonia fuel cells (DAFC) using nanoporous silicon (PS) as proton conducting membrane (instead of traditional polymer Nafion membrane) and TiO2, Au/TiO2 or Au as catalyst layer. Porous silicon layers have been prepared by electrochemical modification of silicon substrates. Films containing titanium dioxide are more efficient catalysts for hydrogen production from ammonia solution. The Au/ TiO2/PS/Si cell exhibited the open circuit voltage 0.87 V and performance of 1.6 mW/cm2 with 50% ammonia solution as fuel at room temperature. Mechanisms of proton transport in nanoporous silicon membrane and generation of electricity in DAFC have been considered. Advantages of investigated direct ammonia fuel cells consist in simplicity of fabrication technology, which can be integrated into standard silicon micro fabrication processes and operation of cells at room temperature. The work demonstrates that the PS based fuel cells have potential for portable applications.展开更多
基金Supported by the National Natural Science Foundation of China (29773031).
文摘The supported Au/TiO2 and Au/TiO2-SiO2 catalysts were prepared by deposition precipitation method. The TPD study reveals that propylene oxide competes with propylene to be adsorbed on the same adsorptive center-Ti^n＋ site on the surface of the catalyst and that the adisorbing capacity of the catalyst for propylene oxide is larger than that for propylene. Catalytic behavior for propylene epoxidation with H2 and O2 was tested in a micro-reactor. Under typical conditions, the selectivity for propylene oxide is over 87%. The TG curves show that PO successive oxidation cause carbon deposition on the active center and deactivation of the Au catalysts. Because the amounts of Tin＋ site decrease significantly, and consequently the separation between Ti^n＋ sites increases, the Au/TiO2-SiO2 catalyst is more stable than Au/TiO2.
文摘The objective of the paper is to report results on fabrication, structural, morphological and performance characteristics of novel TiO2/PS/Si, Au/TiO2/PS/Si and Au/PS/Si direct ammonia fuel cells (DAFC) using nanoporous silicon (PS) as proton conducting membrane (instead of traditional polymer Nafion membrane) and TiO2, Au/TiO2 or Au as catalyst layer. Porous silicon layers have been prepared by electrochemical modification of silicon substrates. Films containing titanium dioxide are more efficient catalysts for hydrogen production from ammonia solution. The Au/ TiO2/PS/Si cell exhibited the open circuit voltage 0.87 V and performance of 1.6 mW/cm2 with 50% ammonia solution as fuel at room temperature. Mechanisms of proton transport in nanoporous silicon membrane and generation of electricity in DAFC have been considered. Advantages of investigated direct ammonia fuel cells consist in simplicity of fabrication technology, which can be integrated into standard silicon micro fabrication processes and operation of cells at room temperature. The work demonstrates that the PS based fuel cells have potential for portable applications.
