Pt修饰的Pd/石墨烯纳米复合材料的制备及对乙二醇氧化反应的电催化活性

摘要

Pd nanoparticles/graphene (Pd/G) composites were fabricatedvia the chemical reduction method using graphite oxide and palladium nitrate,and then deposition of Pt on Pd/G was performed potentiostatically using chloroplatinic acid as precursor of platinum. Pt-modified Pd/G (Pt-Pd/G) electrodes with different platinum loadings were prepared. The microstructure of the Pt-Pd/G electrode was characterized by FE-SEM,EDX and TEM,and the results showed that metal nanoparticles with a mean diameter of 7.2 nm were evenly distributed on the surface of graphene. Electrochemical measurements revealed the high catalytic activity of Pt-Pd/G electrodes for ethylene glycol oxidation in alkaline solution. The peak current density on the Pt-Pd/G electrodes with a Pt∶Pd atomic ratio of 1∶42 was about 3.0 and 2.7 times higher than that on Pd/G and Pt/G electrodes,respectively. The catalytic activity of the Pd/G electrode was significantly improved by the deposition of a small amount of Pt. The modification method used in this study is simple but its effect is very obvious,and the approach can be used to modify other metal substrates with a second metal.%以氧化石墨（GO）和Pd(NO3)2为原料，通过化学还原法制备Pd纳米粒子-石墨烯（Pd/G）纳米复合材料，然后以H2PtCl6作为Pt前体，在Pd纳米粒子的表面恒电位沉积Pt，制备不同Pt负载量的Pd/G（Pt-Pd/G）电极。利用场发射扫描电镜（FE-SEM）、透射电镜（TEM）和X射线能谱仪（EDX）对材料的微观结构进行了表征和分析。结果显示石墨烯上的金属粒子分散均匀，平均粒径约7.2nm。电化学测试结果显示Pt-Pd/G电极对乙二醇电化学氧化反应具有良好的催化性能。当纳米粒子的Pt∶Pd原子百分比为1∶42时，其反应峰电流密度分别为Pd/G和Pt/G电极的3.0倍和2.7倍。少量的Pt沉淀可显著改进Pd/G电极的催化活性。本研究采用的修饰方法简单，修饰效果明显，可应用于其他金属纳米复合材料的异金属修饰。