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通过在Au电极表面欠电位沉积(UPD)Cu、再与Pt源(H2PtCl6或K2PtCl4)进行置换反应,制得单层级Pt原子修饰的金电极(对H2PtCl6或K2PtCl4,所制电极分别记为Pt(CuUPD-Pt4+)n/Au或Pt(CuUPD-Pt2+)n/Au,n表示欠电位沉积-置换过程的重复次数).用电化学石英晶体微天平(EQCM)技术定量研究了所制电极,评估了其在碱性环境中催化甲醇氧化的质量比活性(SECA).结果表明,以H2PtCl6为Pt源所制电极(Pt(CuUPD-Pt4+)3/Au)的活性更高,最大SECA高达35.7mAμg-1.根据EQCM结果计算了置换效率,籍此讨论了Pt原子在Au电极表面的层层组装结构,发现所制电极表面的裸Au位点分布百分数与实验结果(由AuOx还原峰电量测算)吻合.我们认为,EQCM技术是一种定量研究电极支撑的超薄催化剂的有效手段,这种高效的单层级贵金属催化剂有望在生物、能源、环境相关的电催化研究中进一步应用.
A single-level Pt atom-modified gold electrode (H2PtCl6 or K2PtCl4) was prepared by underpotential deposition (UPD) of Cu on the surface of Au electrode followed by displacement reaction with Pt source (H2PtCl6 or K2PtCl4) (CuUPD-Pt4 +) n / Au or Pt (CuUPD-Pt2 +) n / Au, where n is the number of repetitions of the underpotential deposition-displacement process. The electrochemical impedance spectroscopy (EQCM) The results showed that the activity of Pt (CuUPD-Pt4 +) 3 / Au catalyst with H2PtCl6 as Pt source was higher and its maximum SECA was as high as 35.7 mAμg-1. Based on the results of EQCM, the efficiency of displacement was calculated. The assembly of Pt atoms on the surface of Au electrode was discussed. The percentage distribution of bare Au sites on the surface of the electrode and the experimental results (calculated from AuOx reduction peak charge) ) We believe that the EQCM technique is an effective method for the quantitative study of electrode-supported ultrathin catalysts, and this highly efficient single-level precious metal catalyst is expected to be further applied in bio-energy, environmental-related electrocatalysis.