离子液体中PMBA脱羧反应及界面水影响的电化学SERS研究  

Electrochemical-SERS Investigation on the Decarboxylated Reaction of PMBA in Ionic Liquid and Influence of Interfacial Water

作　　者：秦海敬 贺乾军 徐敏敏[1] 袁亚仙[1] 姚建林[1] QIN Haijing;HE Qianjun;XU Minmin;YUAN Yaxian;YAO Jianlin(College of Chemistry,Chemical Engineering and Materials Science,Soochow University,Suzhou 215123,China)

机构地区：[1]苏州大学材料与化学化工学部,苏州215123

出　　处：《高等学校化学学报》2024年第1期129-135,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:22172109,21773166);江苏省高等学校自然科学研究重大项目(批准号:21KJA150009)资助

摘　　要：基于气-液界面自组装法和转移技术制备了负载Au纳米粒子单层膜的玻碳电极(Au MLF@GC),并将其用于离子液体-电化学体系界面过程现场的研究.以对巯基苯甲酸(PMBA)的表面等离激元共振(SPR)催化脱羧生成苯硫酚(TP)反应为探针,采用电化学-表面增强拉曼光谱(SERS)技术,通过电位阶跃法研究了其在离子液体体系中的反应动力学行为.结果表明,亲水性离子液体[BMIm]BF_(4)/Au MLF@GC的零电荷电位(pzc)为−0.95 V,PMBA脱羧反应仅在pzc以正区间发生;通过SERS谱峰强度变化以二级反应拟合获得该反应的速率常数,发现其反应速率常数的对数与阶跃后电位呈线性关系;随着体系外加水的含量(摩尔分数)由0增至0.001和0.003,阶跃后发生脱羧反应的起始电位负移,且同一阶跃电位下反应速率常数随着外加水量的增加而增大.Based on the gas-liquid interface self-assembly method and transfer technology,a glassy carbon electrode loaded with Au nanoparticles monolayer(Au MLF@GC)was prepared,and it was employed to in situ study the interfacial processes of ionic liquid electrochemical systems.The decarboxylation of p-mercaptobenzoic acid(PMBA)catalyzed by surface plasmon resonance(SPR)to phenylthiophenol(TP)as the probe reaction,the electrochemical surface-enhanced Raman spectroscopy(SERS)was developed to investigated the kinetic behaviours of the reaction of PMBA in[BMIm]BF_(4)systems via the potential-step method.The potential of zero charge(pzc)of the hydrophilic ionic liquid[BMIm]BF_(4)/Au MLF@GC was determined to be−0.95 V by the differential capacitance and i-t measure⁃ments for electrode immersion.The decarboxylation of PMBA occurred in the positive region of the pzc,and the reaction rate constant was determined based on the second order kinetic reaction and change of the SERS intensities of relevant peaks.The linear relationship between the logarithm of the reaction rate constant and the step potential was resolved.With the addition of extra-water(XW)from 0 to 0.001 and 0.003(molar ratio),the initial step potential was shifted negatively,and the reaction rate constant increased with the addition of water at the same step potential.

关 键 词：离子液体 表面增强拉曼光谱 电化学 脱羧反应速率常数 零电荷电位 

分 类 号：O646.2[理学—物理化学]