A large scale Palladium nanowire array was directly grown on the surface of glassy carbon electrode by direct current electrolysis with the help of anodic aluminum oxide template.High-resolved SEM photographs have ind...A large scale Palladium nanowire array was directly grown on the surface of glassy carbon electrode by direct current electrolysis with the help of anodic aluminum oxide template.High-resolved SEM photographs have indicated that the Palladium nanowire arrays were highly uniform and ordered.The diameter of single Pd nanowire was about 30 nm,which agreed well with the porous diameter of used template.Meanwhile,the electrocatalytic activity of Pd NWAs electrodes for ethanol oxidation in alkaline media was studied.It is found that the obtained nanostructurs exhibit excellent catalytic activity for ethanol.展开更多
采用无电镀Pd的方法,在硅纳米线上制备了一层Pd.首次制备出了能够在室温下工作的Pd/SiNWs肖特基氢气传感器.SEM(Scanning Electron Microscopy)(扫描电子显微镜)表征结果表明,硅纳米线表面Pd层是由Pd纳米颗粒组成.Pd/SiNWs肖特基二极管...采用无电镀Pd的方法,在硅纳米线上制备了一层Pd.首次制备出了能够在室温下工作的Pd/SiNWs肖特基氢气传感器.SEM(Scanning Electron Microscopy)(扫描电子显微镜)表征结果表明,硅纳米线表面Pd层是由Pd纳米颗粒组成.Pd/SiNWs肖特基二极管I-V测试结果表明,该传感器可以在室温下进行氢气(H2)浓度的检测,且可检测的浓度范围很大,同时给出了Pd/SiNWs/p-Si肖特基二极管在常温下进行检测H_2的敏感机理.实验表明,这种新型传感器可以在室温下进行H2检测,且具有很大的发展潜力,可以应用于燃料电池等诸多领域.展开更多
We have dispersed individual Pd atoms onto ZnO nanowires(NWs)as single‐atom catalysts(SACs)and evaluated their catalytic performance for several selected catalytic reactions.The Pd1/ZnO SAC is highly active,stable,an...We have dispersed individual Pd atoms onto ZnO nanowires(NWs)as single‐atom catalysts(SACs)and evaluated their catalytic performance for several selected catalytic reactions.The Pd1/ZnO SAC is highly active,stable,and selective towards CO2for steam reforming of methanol to produce hydrogen.This catalyst system is active for oxidation of CO and H2but performs poorly for preferential oxidation of CO in hydrogen‐rich stream primarily due to the strong competitive oxidation of H2on ZnO supported Pd1atoms.At ambient pressure,reverse water‐gas‐shift reaction occurs on the Pd1/ZnO SAC.This series of tests of catalytic reactions clearly demonstrate the importance of selecting the appropriate metal and support to develop SACs for catalytic transformation of molecules.展开更多
Employing the accurate frozen-core full-potential projector augmented-wave method,the self-consistentelectronic structure calculations were carried out on pure Ni,Pd,Pt and mixed Ni-Pd and Ni-Pt free-standing linear a...Employing the accurate frozen-core full-potential projector augmented-wave method,the self-consistentelectronic structure calculations were carried out on pure Ni,Pd,Pt and mixed Ni-Pd and Ni-Pt free-standing linear andzigzag nanowires.The bond lengths for all these systems are generally increased as their structures change from the linearto the zigzag chain.The bond lengths for Ni-Pd and Ni-Pt wires are in between the values of corresponding pure systemand the bond angles around 60° suggesting the possible formation of Ni-Pd and Ni-Pt bimetallic materials.In mixedNi-Pd and Ni-Pt chains,the Ni,Pd,and Pt atoms have quite high local magnetic moments.The calculations suggestthat the magnetic moments in linear nanowires are generally larger than the ones of corresponding zigzag nanowires.Itis found that there is hybridization between Ni 3d and Pd 4d,Ni 3d and Pt 5d states,which may significantly affectstructural stability and magnetism of Ni-Pd and Ni-Pt nanowires.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
文摘A large scale Palladium nanowire array was directly grown on the surface of glassy carbon electrode by direct current electrolysis with the help of anodic aluminum oxide template.High-resolved SEM photographs have indicated that the Palladium nanowire arrays were highly uniform and ordered.The diameter of single Pd nanowire was about 30 nm,which agreed well with the porous diameter of used template.Meanwhile,the electrocatalytic activity of Pd NWAs electrodes for ethanol oxidation in alkaline media was studied.It is found that the obtained nanostructurs exhibit excellent catalytic activity for ethanol.
文摘采用无电镀Pd的方法,在硅纳米线上制备了一层Pd.首次制备出了能够在室温下工作的Pd/SiNWs肖特基氢气传感器.SEM(Scanning Electron Microscopy)(扫描电子显微镜)表征结果表明,硅纳米线表面Pd层是由Pd纳米颗粒组成.Pd/SiNWs肖特基二极管I-V测试结果表明,该传感器可以在室温下进行氢气(H2)浓度的检测,且可检测的浓度范围很大,同时给出了Pd/SiNWs/p-Si肖特基二极管在常温下进行检测H_2的敏感机理.实验表明,这种新型传感器可以在室温下进行H2检测,且具有很大的发展潜力,可以应用于燃料电池等诸多领域.
基金funded by the National Science Foundation (CHE-1465057)
文摘We have dispersed individual Pd atoms onto ZnO nanowires(NWs)as single‐atom catalysts(SACs)and evaluated their catalytic performance for several selected catalytic reactions.The Pd1/ZnO SAC is highly active,stable,and selective towards CO2for steam reforming of methanol to produce hydrogen.This catalyst system is active for oxidation of CO and H2but performs poorly for preferential oxidation of CO in hydrogen‐rich stream primarily due to the strong competitive oxidation of H2on ZnO supported Pd1atoms.At ambient pressure,reverse water‐gas‐shift reaction occurs on the Pd1/ZnO SAC.This series of tests of catalytic reactions clearly demonstrate the importance of selecting the appropriate metal and support to develop SACs for catalytic transformation of molecules.
基金Supported by the National Natural Science Foundation of China under Grant Nos.50531040 and 50871058the Ministry of Science and Technology of China under Grant No.2006CB605201
文摘Employing the accurate frozen-core full-potential projector augmented-wave method,the self-consistentelectronic structure calculations were carried out on pure Ni,Pd,Pt and mixed Ni-Pd and Ni-Pt free-standing linear andzigzag nanowires.The bond lengths for all these systems are generally increased as their structures change from the linearto the zigzag chain.The bond lengths for Ni-Pd and Ni-Pt wires are in between the values of corresponding pure systemand the bond angles around 60° suggesting the possible formation of Ni-Pd and Ni-Pt bimetallic materials.In mixedNi-Pd and Ni-Pt chains,the Ni,Pd,and Pt atoms have quite high local magnetic moments.The calculations suggestthat the magnetic moments in linear nanowires are generally larger than the ones of corresponding zigzag nanowires.Itis found that there is hybridization between Ni 3d and Pd 4d,Ni 3d and Pt 5d states,which may significantly affectstructural stability and magnetism of Ni-Pd and Ni-Pt nanowires.
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,
