(1.中南工业大学冶金物理化学与化学新材料研究所,长沙 410083;
2.深圳中金实业股份有限公司, 深圳 518000)
摘 要: 采用二步法先合成钾的石墨层间化合物,然后再通过它合成Co, Ni系石墨层间化合物。化学分析、 X射线衍射、X射线光电子能谱及透射电镜的分析结果表明,这些化合物中金属主要以正2价形态存在,化合物的粒度为纳米级。用微电极测试了它们在KOH溶液中对氧还原的催化活性,发现C48Co及C48Ni为好,尤以C48Co为优;加入C48Co的气体扩散电极的电流密度,比未加的高68倍。用旋转圆盘电极研究了对氧的还原过程, 发现该过程同时受扩散与化学反应两种作用的混合控制,反应电子数为2。
关键字: 镍 钴 石墨层间化合物
(1.Institute of Metallurgical Physicochemistry and Chemical Materials,Central South University of Technology, Changsha 410083, P. R. China;
2.Shenzhen Zhongjin Corp. Ltd, Shenzhen 518000, P. R. China)
Abstract:Graphite intercalation compounds(GICs)-Co and GICs-Ni have been successfully synthesized with the GICs-K as intermediates, and the compounds have been analyzed with chemical analysis, X-ray diffraction, X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM). The valences of Co and Ni in the compounds are both +2. The particle size of these compounds is in the order of nm. The experimental results of powder microelectrodes indicated that C48Co is the best one for oxygen reduction among all the GICs-Co and GICs-Ni compounds studied. The soft embeded rotating disk electrode(RDE) experiments indicated oxygen reduction on the surface of GICs-Co is jointly controlled by diffusion and electr ochemical reaction, the number of electron transfer of oxygen reduction is 2. The preparation of peroxides using gas diffusion electrodes with catalyst C48Co indicated that the cathodic current density is 68 times higher than that without C48Co, the current efficiency is 93%.
Key words: nickel cobalt graphite intercalation compound