碳载体预处理对纳米Pt/C电催化性能影响

摘要

利用NaBH4还原机制，采用经不同方法预处理的碳载体成功制备出Pt/C-HNO3、 Pt/C-H2O2和Pt/C 3种碳载铂纳米催化剂。通过扫描电镜（SEM）、透射电镜（HR-TEM）、循环伏安（CV）和 COad溶出技术进行表征。结果表明，所制备的催化剂大小分布较为均一，平均粒径约为4 nm；HR-TEM观察发现，Pt/C-HNO3中铂纳米粒子的表面具有较高的台阶原子密度；在COad溶出实验中Pt/C-HNO3表现出较强的抗一氧化碳毒化能力；所制备的3种催化剂及商业催化剂Pt/C JM对乙醇氧化的电催化活性顺序为：Pt/C-HNO3> Pt/C-H2O2> Pt/C > Pt/C JM，其中Pt/C-HNO3的电催化活性和稳定性分别为Pt/C JM的1.5倍和1.9倍。%Carbon supported Pt nanocatalysts (Pt/C) are widely used in fuel cells. In this work, three kinds of Pt/C catalysts were successfully preparedvia a chemical reduction method by using carbon black pretreated with different methods,i.e., HNO3-pretreated carbon (Pt/C-HNO3), H2O2-pretreated carbon (Pt/C-H2O2) and unpretreated carbon (Pt/C). The morphologies and properties of the as-prepared Pt/C catalysts were characterized by SEM, HR-TEM, CV and COadstripping. Pt nanoparticles were dispersed well in these three Pt/C catalysts with average particle size of 3.4, 3.9 and 4.5 nm respectively. HR-TEM observation indicated that Pt/C-HNO3 possessed high-density of step atoms and COad stripping experiments showed that Pt/C-HNO3 exhibited the best anti-poisoning property. Comparing the catalytic activities of three as-prepared Pt/C catalysts toward ethanol electrooxidation with commercial Pt/C catalyst (Pt/C JM) showed that the as-prepared catalystsexhibited higher activity and stability than those of Pt/C JM and the order was Pt/C-HNO3>Pt/C-H2O2>Pt/C>Pt/C JM. Especially for Pt/C-HNO3, its activity and stability were 1.5 times and 1.9 times of those of Pt/C JM respectively.