A successful approach to prepare the Pd-Ni nanowire arrays electrode without carbon supports was reported. The morphology and crystallinity of nanowire were characterized by transmission electron microscopy, selected-...A successful approach to prepare the Pd-Ni nanowire arrays electrode without carbon supports was reported. The morphology and crystallinity of nanowire were characterized by transmission electron microscopy, selected-area electron diffraction （SAED）, X-ray diffrac- tion （XRD）, and X-ray photoelectron spectroscopy （XPS） analyses, respectively. The results show that the diameters of the nanowire are in the range of 65-75 nm, and the polycrystalline binary solid solution alloy is formed in the Pd-Ni nanowire. Cyclic voltammograms, chronoampero- grams, and electrochemical impedance spectroscopy dem- onstrate that the Pd-Ni nanowire arrays electrodes show excellent electrocatalytic performance for methanol oxi- dation in alkaline media. The catalytic activity of Pd-Ni nanowire arrays electrode is ,,~ 1.39 times higher than that of the Pd nanowire arrays electrode and ,,~2.28 times higher than that of the commercial Pd/C catalyst. This is mostly owing to the transfer of electron density from Ni to Pd. These results indicate that Pd-Ni nanowire arrays electrode is very promising in an alkaline direct methanol fuel cell.展开更多
Carbon-supported PtPdRuIr, Pd@PtRuIr, PtPd@PtRuIr, and PtPdRu@PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively...Carbon-supported PtPdRuIr, Pd@PtRuIr, PtPd@PtRuIr, and PtPdRu@PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively investigated at room temperature. The catalysts were characterized by transmission electron microscopy and X-ray diffraction techniques, and their electrochemical behavior was evaluated by the cyclic voltammetry. The PtPdRu@PtRuIr/C catalyst is found to yield much higher electrocatalytic activity than the other ones and the commercial catalyst. For example, the Pt metal mass-specific activity of this PtPdRu@PtRuIr/C（Pt content 10 wt%,1.7 mAácm-2ámg-1） electrocatalyst is ＊3-fold higher than that of the commercial JM 40 % Pt/C（0.6 mAácm-2ámg-1）electrocatalysts, and the If/Ib ratio of PtPdRu@PtRuIr/C is1.6, which is higher than that of the JM 40 % Pt/C（0.9）. The improvement may result from the high dispersion of the active metal catalyst and the synergistic effect between the PtRuIr and PtPdRu layers. It is thus concluded that the pseudo-core-shell structure could significantly improve the methanol electro-oxidation activity and CO tolerance of the electrocatalyst.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51164017 and 20863003)
文摘A successful approach to prepare the Pd-Ni nanowire arrays electrode without carbon supports was reported. The morphology and crystallinity of nanowire were characterized by transmission electron microscopy, selected-area electron diffraction （SAED）, X-ray diffrac- tion （XRD）, and X-ray photoelectron spectroscopy （XPS） analyses, respectively. The results show that the diameters of the nanowire are in the range of 65-75 nm, and the polycrystalline binary solid solution alloy is formed in the Pd-Ni nanowire. Cyclic voltammograms, chronoampero- grams, and electrochemical impedance spectroscopy dem- onstrate that the Pd-Ni nanowire arrays electrodes show excellent electrocatalytic performance for methanol oxi- dation in alkaline media. The catalytic activity of Pd-Ni nanowire arrays electrode is ,,~ 1.39 times higher than that of the Pd nanowire arrays electrode and ,,~2.28 times higher than that of the commercial Pd/C catalyst. This is mostly owing to the transfer of electron density from Ni to Pd. These results indicate that Pd-Ni nanowire arrays electrode is very promising in an alkaline direct methanol fuel cell.
基金financially supported by the National Natural Scientific Foundation of China (Nos. 20673040 and20876062)Guangdong Provincial Scientific Foundation (Nos. 36055 and S2012040007383)the Key Laboratory of Fuel Cell Technology of Guangdong Province (No. 201112)
文摘Carbon-supported PtPdRuIr, Pd@PtRuIr, PtPd@PtRuIr, and PtPdRu@PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively investigated at room temperature. The catalysts were characterized by transmission electron microscopy and X-ray diffraction techniques, and their electrochemical behavior was evaluated by the cyclic voltammetry. The PtPdRu@PtRuIr/C catalyst is found to yield much higher electrocatalytic activity than the other ones and the commercial catalyst. For example, the Pt metal mass-specific activity of this PtPdRu@PtRuIr/C（Pt content 10 wt%,1.7 mAácm-2ámg-1） electrocatalyst is ＊3-fold higher than that of the commercial JM 40 % Pt/C（0.6 mAácm-2ámg-1）electrocatalysts, and the If/Ib ratio of PtPdRu@PtRuIr/C is1.6, which is higher than that of the JM 40 % Pt/C（0.9）. The improvement may result from the high dispersion of the active metal catalyst and the synergistic effect between the PtRuIr and PtPdRu layers. It is thus concluded that the pseudo-core-shell structure could significantly improve the methanol electro-oxidation activity and CO tolerance of the electrocatalyst.
