ZnO bicrystalline nanosheets have been synthesized by using Ax=AU1-x alloy catalyst via the vapor transport and condensation method at 650 ℃. High resolution transmission electron microscopy characterization reveals ...ZnO bicrystalline nanosheets have been synthesized by using Ax=AU1-x alloy catalyst via the vapor transport and condensation method at 650 ℃. High resolution transmission electron microscopy characterization reveals a twin boundary with {01-13} plane existing in the bicrystalline. A series of control experiments show that both AgxAu1-x alloy catalyst and high supersaturation of Zn vapor are prerequisites for the formation of ZnO bicrystalline nanosheet. Moreover, it is found that the density of ZnO bicrytalline nanosheets can be tuned through varying the ratio of Ag to Au in the alloy catalyst. The result demonstrates that new complicated nanostructures can be produced controllably with appropriate alloy catalyst.展开更多
Bimetallic palladium-gold （PdAu） catalysts have better catalytic performance than monometallic catalysts for many applications. PdAu catalysts with controlled nanostructures and enhanced activi- ties have been exten...Bimetallic palladium-gold （PdAu） catalysts have better catalytic performance than monometallic catalysts for many applications. PdAu catalysts with controlled nanostructures and enhanced activi- ties have been extensively studied but their syntheses require multiple and occasionally complicated steps, In this work, we demonstrated that supported PdAu catalysts could be simply prepared by doping a supported Pd catalyst with gold through wet impregnation and calcination. Resulting PdAu-on-carbon （PdAu/C） catalysts were tested for the room-temperature, aqueous-phase hydro- dech/orination of trichloroethene. The most active PdAu/C catalyst （Pd 1.0 wt%, Au 1.1 wt%, dried/air/H2 process] had an initial turnover frequency （TOF] of 34.0×10^-2 mOITcE mOled-1 S-1, which was 〉15 times higher than monometallic Pd/C （Pd 1,0 wt%, initial TOF of 2.2 ×10^-2 molTCE molpd^-1s^-1）. Through X-ray absorption spectroscopy, the gold kept Pd from oxidizing under calcination at 400℃. Probable nanostructure evolution pathways are proposed to explain the observed catalysis,展开更多
基金ACKNOWLEDGMENTS This work was supported by the Ministry of Science and Technology of China of China （No.2011CB921403）, the National Natural Science Foundation of China （No. 11374274 and No. 11074231）, and Chinese Academy of Sciences （No.XDB01020000）.
文摘ZnO bicrystalline nanosheets have been synthesized by using Ax=AU1-x alloy catalyst via the vapor transport and condensation method at 650 ℃. High resolution transmission electron microscopy characterization reveals a twin boundary with {01-13} plane existing in the bicrystalline. A series of control experiments show that both AgxAu1-x alloy catalyst and high supersaturation of Zn vapor are prerequisites for the formation of ZnO bicrystalline nanosheet. Moreover, it is found that the density of ZnO bicrytalline nanosheets can be tuned through varying the ratio of Ag to Au in the alloy catalyst. The result demonstrates that new complicated nanostructures can be produced controllably with appropriate alloy catalyst.
基金supported by the National Science Foundation,United States(EEC-0647452)the Welch Foundation(C-1676)~~
文摘Bimetallic palladium-gold （PdAu） catalysts have better catalytic performance than monometallic catalysts for many applications. PdAu catalysts with controlled nanostructures and enhanced activi- ties have been extensively studied but their syntheses require multiple and occasionally complicated steps, In this work, we demonstrated that supported PdAu catalysts could be simply prepared by doping a supported Pd catalyst with gold through wet impregnation and calcination. Resulting PdAu-on-carbon （PdAu/C） catalysts were tested for the room-temperature, aqueous-phase hydro- dech/orination of trichloroethene. The most active PdAu/C catalyst （Pd 1.0 wt%, Au 1.1 wt%, dried/air/H2 process] had an initial turnover frequency （TOF] of 34.0×10^-2 mOITcE mOled-1 S-1, which was 〉15 times higher than monometallic Pd/C （Pd 1,0 wt%, initial TOF of 2.2 ×10^-2 molTCE molpd^-1s^-1）. Through X-ray absorption spectroscopy, the gold kept Pd from oxidizing under calcination at 400℃. Probable nanostructure evolution pathways are proposed to explain the observed catalysis,
