Controllable Synthesis of Tetragonal and Cubic Phase Cu2Se Nanowires Assembled by Small Nanocubes and Their Electrocatalytic Performance for Oxygen Reduction Reaction

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• 作者：Suli Liu ; Zengsong Zhang ; Jianchun Bao ; Yaqian Lan ; Wenwen Tu ; Min Han ; Zhihui Dai
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：July 25, 2013
• 年：2013
• 卷：117
• 期：29
• 页码：15164-15173
• 全文大小：573K
• 年卷期：v.117,no.29(July 25, 2013)
• ISSN：1932-7455

文摘

The rich phase structure of Cu₂Se may provide good opportunities for modulating and optimizing their catalytic properties. However, chemical synthesis of Cu₂Se nanostructures with different crystal phases still is a key challenge, and their catalytic application in energy fields has not been studied. In this paper, pure tetragonal and cubic phases Cu₂Se nanowires (NWs) that assembled by small nanocubes have been controllably synthesized via a simple solid鈥搇iquid phase chemical transformation method, i.e., thermal treatment of presynthesized Cu NWs in Se precursor solution containing proper surfactant and 1-octadecene. Besides reaction temperature and ripening time, the functional groups and alkyl chain length of used surfactant greatly affect the kinetics of the transformation reaction and phase structure control of Cu₂Se NWs. The trioctylphosphine is found to be the optimal surfactant, which not only accelerates the transformation reaction but also improves the stable temperature of tetragonal phase Cu₂Se NWs about 80 掳C compared with that of their bulk counterparts. Electrochemical tests reveal that both the obtained Cu₂Se NWs can be used to catalyze oxygen reduction reaction (ORR) in alkaline media. But the catalytic performance of tetragonal phase Cu₂Se NWs is much higher than that of cubic phase ones, which is even better than that of commercial Pd/C and some reported non-Pt electrocatalysts. The diverse catalytic performances of those Cu₂Se NWs result from their distinct spatial arrangement means of Cu and Se atoms that lead to different adsorption and activation of O₂ molecules approaches, as evidenced by electrocatalytic dynamic experiments. The ORR on tetragonal phase Cu₂Se NWs abides by the direct 4e^{鈥?/sup> mechanism, whereas that on cubic phase ones complies with dual-path mechanism comprising both 2e鈥?/sup> and 4e鈥?/sup> pathways.}