壳层厚度可调控的Ag@Pd@Pt纳米粒子的合成和甲酸电催化研究

在本课题组研究55 nm Au@Pd@Pt对甲酸电催化效果基础上，我们采用Ag取代Au制备55 nm Ag@Pd@Pt纳米粒子以降低催化剂的成本，并对甲酸的电催化行为进行研究. 研究表明：少量Pt的存在可大幅度提高催化剂的活性，当Pt的覆盖度为0.5 单原子层（ML）时，起始氧化电位最为靠前，氧化峰电流最大，这与Au@Pd@Pt纳米粒子对甲酸电催化行为类似. 与Au@Pd@Pt纳米粒子相比，其最佳起始氧化电位偏正0.05 V，但电催化活性并没有明显的降低. 通过改变催化剂比表面积研究甲酸的电催化行为，发现将9 nm Ag纳米粒子作为内核的9 nm Ag@Pd@Pt负载在活性炭中，在保持催化活性不变的情况下，碳载的催化剂价格可比55 nm Au@Pd@Pt纳米粒子降低220倍左右.

Syntheses of Ag@Pd@Pt Nanoparticles with Tunable Shell Thickness for Electrochemical Oxidation of Formic Acid

In an effort to lower cost of a catalyst, the silver (Ag) core with palladium (Pd) layer then platinum (Pt) island (Ag@Pd@Pt) nanoparticles were synthesized and the electrocatalytic activity of Ag@Pd@Pt nanoparticles on formic acid was compared with that of Au@Pd@Pt nanoparticles reported previously. The results showed that the existence of a small amount of Pt could significantly improve the activity of the catalyst. When the surface coverage of Pt approached 0.5 monolayers, the activity of Ag@Pd@Pt nanoparticles reached the maximum. Though the onset potential of the electro-oxidation was slightly more positive (about 50 mV), the overall electrocatalytic activity of Ag@Pd@Pt nanoparticles was similar to that of the Au@Pd@Pt nanoparticles. The relationship between the changing specific surface area and the electrocatalytic activity behavior of Ag@Pd@Pt nanoparticles in formic acid was also studied. The price of Ag@Pd@Pt nanoparticles with Ag core of 9 nm supported by activated carbon was ~ 220 times lower than that of 55 nm Au@Pd@Pt nanoparticles based on the similar electocatalytic activity being obtained.