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铜基银枝晶的制备和氧还原电催化性能
引用本文:赵秀华,陈福义,刘婧.铜基银枝晶的制备和氧还原电催化性能[J].贵金属,2012,33(1):21-28.
作者姓名:赵秀华  陈福义  刘婧
作者单位:西北工业大学凝固技术国家重点实验室,西安,710072
基金项目:国家自然科学基金,西北工业大学基础研究基金,凝固技术国家重点实验室自主研究课题
摘    要:通过迦尔瓦尼置换反应在不同的Ag+溶液中制备出了铜基银枝晶,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电化学工作站分别对样品的结构、微观形貌以及电化学性能进行了表征。结果表明,随着溶液中Ag+浓度和反应时间的增加,银的形貌从团簇状向树枝状转变,氧还原电催化性能也增强;在相同浓度Ag+溶液中,SO42-比NO3-更能促进枝晶的生长,但当阴离子是NO3-时比阴离子是SO42-时所制备的银枝晶的氧还原电催化性能更好;在10 mmol/L AgNO3溶液中,反应时间为1800 s时制备的银枝晶电极使H2O2的还原峰电流最大,在0.1 mol/L Na2SO4+5mmol/L H2O2溶液中,恒电位为-0.32 V时,其稳态电流密度可达2.83 mA/cm2。初步提出了银枝晶的生长机制和H2O2的氧还原催化机制。

关 键 词:迦尔瓦尼置换反应  银枝晶  氧还原  稳态电流密度

Preparation and Electrocatalytic Properties for Oxygen Reduction of Silver Dendrite Crystals on Copper Substrates
ZHAO Xiuhua , CHEN Fuyi , LIU Jing.Preparation and Electrocatalytic Properties for Oxygen Reduction of Silver Dendrite Crystals on Copper Substrates[J].Precious Metals,2012,33(1):21-28.
Authors:ZHAO Xiuhua  CHEN Fuyi  LIU Jing
Affiliation:(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xian 710072)
Abstract:This paper reports the preparation of silver dendrite crystals based on galvanic displacement reaction of copper substrates in aqueous solutions containing various Ag+ ion.Their microstructure,morphology and electrocatalytic properties were characterized by XRD,SEM and electrochemical workstation.The results demonstrated that with increasing of Ag+ ion concentration and reaction time,the morphology of silver evolves from cluster-like crystal to dendrite crystal,and the electrocatalytic properties for oxygen reduction of silver dendrites are increased.Under the same Ag+ ion concentration,the growth rate of Ag dendrites is much fast in Ag+ ion solutions with SO42-,but the electrocatalytic properties for oxygen reduction of Ag dendrites made from the solution of NO3-are stronger than that made from the solution of SO42-.Ag dendrite electrodes show the maximum peak current of H2O2 reduction under reaction time of 1800 s using 10 mmol/L AgNO3 solution.With constant potential at-0.32 V in 0.1 mol/L Na2SO4 + 5 mmol/L H2O2 solution,its steady-state current density is up to 2.83 mA/cm2.The growth mechanism of silver dendrites and the mechanism for oxygen reduction of H2O2 were proposed tentatively.
Keywords:galvanic displacement reaction  silver dendrites  oxygen reduction  steady-state current density
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