摘要
采用化学还原和电位置换法制备了CoPt纳米空心球,该催化剂对甲醇氧化表现出较好的电催化活性.透射电镜(TEM)、能量散射光谱(EDS)和电化学循环伏安实验结果表明,在0.1mol·L-1H2SO4+0.1mol·L-1CH3OH中进行测试时,CoPt纳米空心球发生了去合金化过程,催化剂表面Co元素溶解,形成了富Pt表面,表现出更好的电催化活性,同时表现出较好的结构稳定性.采用原位电化学红外光谱在分子水平研究了CoPt纳米空心球上甲醇氧化过程,发现甲醇在CoPt纳米空心球氧化中间产物主要为CO,且CO表现出异常红外效应,与CO为探针分子在CoPt纳米空心球上得到的红外光谱结果一致.研究结果表明,去合金化方法是一种有效调节催化剂表面组成和性能的手段,原位电化学红外光谱是潜在的原位研究有机小分子氧化机理的方法,在燃料电池中将得到广泛的应用.
Hollow CoPt nanospheres were synthesized by chemical reduction and galvanic displacement reactions. The catalyst showed good electrocatalytic activity for methanol oxidation. The results of transmission electron microscopy （TEM）, energy dispersive spectromenter （EDS）, and electrochemical cyclic voltammograms indicated that, in the process of electrochemical experiments carried in 0.1 mol. L-1 H2SO4 and 0.1 mol. L-1 CH3OH, hollow CoPt nanospheres were dealloying, which induced the dissolution of elemental Co from the surface of the catalyst. After the dealloying process, more Pt active sites were exposed on the surface of the catalyst and the catalyst showed better catalytic activity, as well as enhanced structural stability. The electrooxidation of methanol on the hollow CoPt nanospheres was studied on the molecular level using in situ electrochemical Fourier transform infrared （FTIR） spectroscopy. The toxic intermediate CO observed on the CoPt nanorods displayed abnormal infrared effects （AIREs）. The FTIR results were similar to those obtained in an earlier experiment on the hollow CoPt nanospheres using CO as a probe molecule. All the results suggested that the dealloying method would be a useful technique forregulating the composition and performance of the catalyst. In situ electrochemical FTIR was highlighted as a potential method for studying the oxidation processes of organic molecules. It is envisaged that these methods will be widely used in the field of fuel cell research.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2012年第9期2071-2076,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20833005)资助项目~~
