Pt/RuO2/CNTs纳米催化剂中RuO2含量对甲醇电催化氧化性能的影响

制备了一种新的甲醇直接燃料电池Pt/RuO2/CNTs阳极催化剂,在相同Pt负载量下,其甲醇电催化氧化活性是Pt/CNTs的3倍.采用循环伏安法研究发现Pt/RuO2/CNTs纳米催化剂中RuO2含量对甲醇电催化氧化活性有明显影响,当Pt和RuO2在碳纳米管上含量分别为15%和9.5%时,Pt/RuO2/CNTs催化剂具有最佳的甲醇电催化氧化活性.RuO2负载在碳纳米管上比电容的变化,反映了水合RuO2结构中质子与电子传输平衡的能力,分析表明,催化剂中RuO2含量不同导致电容的变化是影响甲醇电催化氧化活性的主要原因.当催化剂结构中质子与电子传输达到平衡时,催化剂比电容最大,电催化氧化活性最高.这种基于电容关联电催化剂的观点对甲醇直接燃料电池阳极催化剂的设计非常有意义.

Effects of RuO2 Content in Pt/RuO2/CNTs Nanocatalyst on the Electrocatalytic Oxidation Performance of Methanol

A novel Pt/RuO2/CNTs anodic catalyst was prepared for direct methanol fuel cells (DMFC). Compared to Pt/CNTs with the same Pt loading,the activity of Pt/RuO2/CNTs for electrocatalytic oxidation of methanol is 3 times higher. The electrocatalytic activity of Pt/RuO2/CNTs with different RuO2 contents was investigated by cyclic voltammetry. It was observed that the electrocatalytic performance of Pt/RuO2/CNTs was strongly dependent on the RuO2 content. The Pt/RuO2/CNTs catalyst with 15% Pt and 9.5% RuO2 exhibits the best eletrocatalytic methanol oxidation activity. The specific capacitance change of RuO2/CNTs,determined by the matching degree of proton conductivity and electron transfer,is the main reason for the change of electrocatalytic methanol oxidation activity of Pt/RuO2/CNTs with different RuO2 contents. The novel electrocatalyst design concept based on capacitance may be very useful in designing electrocatalysts for DMFC.