材料期刊网

以氧化石墨烯、SnCl2、H2 PtCl6和乙二醇为原料,利用多元醇一步还原法制备高负载量的Pt-Sn/石墨烯催化剂,待反应结束后对反应液加入稀HNO3进行酸处理。通过XRD、ICP、TEM及循环伏安分析不同pH值酸处理下,Pt-Sn/石墨烯催化剂形貌结构、成分和电催化性能,讨论Pt和Sn颗粒在石墨烯表面负载率变化。结果表明,不同pH值时石墨烯均为良好载体；随酸处理程度的增加,Sn含量相应增加,复合材料对乙醇的电催化活性逐渐提高。在pH值为2时,Pt和Sn金属颗粒形成最佳协同效应,催化活性提高了1.2倍。

Pt-Sn/graphene catalysts were prepared by heat treatment of a dispersion of graphene oxide, SnCl2 and H2 PtCl6 in eth-ylene glycol at 130℃ for 3 h after its pH value had been adjusted to 12 by NaOH, followed by centrifuging, washing with ethanol and water, and cryodrying. The pH value of the heat-treated dispersion was controlled by adding dilute nitric acid to 2, 4 and 6 to mediate the properties of the catalysts and its effects on the compositions, microstructure and catalytic activities of the resulting cata-lysts in ethanol electrooxidation. These were investigated by XRD, ICP, TEM and cyclic voltammetry. Results indicated that with decreasing pH values the Sn content increased, the Pt/Sn atom ratio decreased and the electrochemical activity increased. The cur-rent density for ethanol electrooxidation was increased by 120% at the pH value of 2 compared for the sample without nitric acid. The improvement of the catalytic activity can be ascribed to an increased loading of Sn and Pt since the oxidative product of ethylene glycol in the heat treatment acted as a chelating agent for metal nanoparticles under high pH values. A very simple acid-treatment-as-sisted polyol route to prepare graphene supported Pt-Sn nanoparticles were developed. To evaluate the composition, microstructure and electrochemical activity of catalysts treated with different pH values of acid solution have been characterized by XRD、ICP、TEM and cyclic voltammetry. And the changes of Pt and Sn metal particles loading on the surface of graphene were discussed. The results show that graphene is a good support. With the increase of pH values, the Sn content of catalysts increased and the electrochemical activity was improved. As the pH values of acid solution was decreased to 2, the synergistic effect of Pt and Sn reached its maxi-mum, and the current densities of ethanol electrooxidation with the catalysts were about 120% higher than that of original Pt-Sn/G catalysts, which also reached the maximum.