铜基银枝晶的制备和氧还原电催化性能  

Preparation and Electrocatalytic Properties for Oxygen Reduction of Silver Dendrite Crystals on Copper Substrates

作　　者：赵秀华[1] 陈福义[1] 刘婧[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《贵金属》2012年第1期21-28,共8页Precious Metals

基　　金：国家自然科学基金(50971100;50671082);西北工业大学基础研究基金(NPU-FFR-ZC200931);凝固技术国家重点实验室自主研究课题(Grant No.30-TP-2009)

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。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 electroeatalytic 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 re- duction of Ag dendrites made from the solution of NO3 - are stronger than that made from the solution of SQ2-. Ag dendrite electrodes show the maximum peak current of n202 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 H202 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 HE 02 were proposed tentatively.

关 键 词：迦尔瓦尼置换反应 银枝晶 氧还原 稳态电流密度 

分 类 号：O646[理学—物理化学]