离子膜电解法制备氯金酸及其机理探究  

Preparation and mechanism research of chloroauric acid via diaphragm electrolysis

作　　者：杨璋军 吴道新[1] 肖忠良[1] 卢意鹏 张添淳 YANG Zhangjun;WU Daoxin;XIAO Zhongliang;LU Yipeng;ZHANG Tianchun(School of Chemistry and Chemical Engineering,Changsha University of Science&Technology,Changsha 410114,Hunan,China;Shenzhen Yicheng Electronic Technology Co.,Ltd.,Shenzhen 518000,Guangdong,China)

机构地区：[1]长沙理工大学化学化工学院,湖南长沙410114 [2]深圳市溢诚电子科技有限公司,广东深圳518000

出　　处：《精细化工》2023年第4期894-901,共8页Fine Chemicals

基　　金：湖南省战略性新型重大项目(2019GK4041)。

摘　　要：以Au为阳极、石墨为阴极、饱和甘汞电极(SCE)为参比电极、盐酸为电解质,采用离子膜电解法制备了氯金酸。探究了氯金酸制备过程中Au的阳极行为以及实验条件(Cl–浓度、电解液pH、H_(2)O_(2)含量)对制备过程的影响,并对反应机理进行了探究。结果表明,实验所得样品化学式为HAu Cl_(4)·4H_(2)O,氯金酸产率可达94.57%;Au被电解为Au^(3+)发生在阳极电位0.83~1.30 V(vs.SCE)之间,致钝电位为1.3 V(vs.SCE);电解过程中减小电解液pH、增大电解液中Cl–浓度可以促进Au的电解,峰电位随着pH的减小而降低;本实验条件下最佳电解条件为:电解电位1.25 V(vs.SCE)、电解液pH为1.0、Cl–浓度1.0 mol/L、H_(2)O_(2)含量5 mmol。Nyquist图表明,氯金酸电解制备过程受电荷转移与扩散混合控制,随着溶液中Cl–浓度的增大与H_(2)O_(2)的加入,氯金酸制备过程由混合控制向电荷转移控制过渡。Chloroauric acid was prepared by ion-exchange membrane electrolysis using Au as anode,graphite as cathode,saturated calomel electrode(SCE)as reference electrode and hydrochloric acid solution as electrolyte.The anodic behavior of Au during the preparation process and the effects of experimental conditions(Cl–concentration,electrolyte pH,H_(2)O_(2) content)on chloroauric acid production were investigated,followed by exploration on the reaction mechanism.The results showed that the yield of chloroauric acid,in the form of HAuCl_(4)•4H_(2)O,reached 94.57%.The electrolysis of Au to Au^(3+)occurred at an anodic potential of 0.83~1.30 V(vs.SCE)and passivation potential of 1.3 V(vs.SCE).Reducing electrolyte pH and increasing Cl–concentration in electrolyte could promote the electrolysis of Au,and the peak potential decreased with the decrease of pH.The optimum electrolysis conditions of this research were obtained as follows:Anode potential 1.25 V(vs.SCE),electrolyte pH 1.0,Cl–concentration 1.0 mol/L,H_(2)O_(2) content 5 mmol.Data from Nyquist diagram indicated that the electrolytic preparation process of chloroauric acid was controlled by charge transfer and diffusion.And with the increase of Cl–concentration in solution and the addition of H_(2)O_(2),the preparation process of chloroauric acid transited from the mixed control to charge transfer control.

关 键 词：氯金酸 电解法 金 盐酸 双氧水 有机电化学与工业 

分 类 号：TG146[一般工业技术—材料科学与工程]