多孔TiC/TiO_2壳-芯复合物制备、表征分析及应用研究

Preparation, characterization analysis and application of porous TiO_2/TiC shell-core composite

针对PEMWE阳极催化剂,对具有多孔结构和较高比表面积的纳米TiC采用控制氧化进程的方法,进行了表面物相和微孔结构改性,形成多孔结构的TiC-TiO2壳-芯复合物,并以处理后的TiO2-TiC原位复合物作为载体,制成了具有高活性的负载型催化剂。通过X射线衍射光谱法(XRD),布鲁瑙尔-埃利特-特勒法(BET)和透射电子显微镜法(TEM)等多种表征方法,证明了改性后的TiC-TiO2比表面积比TiC增加了2倍以上,具有多矿相复合结构。循环伏安测试表明,Ir/TiC催化剂的析氧峰值电流是Ir黑的5倍,而经过改性后的TiC-TiO2负载的Ir催化剂则是Ir/TiC催化剂的析氧峰值电流的6倍。很明显改性后的TiO2-TiC原位复合物具有更大的比表面积和孔体积,更好地分散了贵金属Ir,大大提高了析氧反应的催化活性。

Phase compositions and microstructure of TiC with high specific surface area and porous structures were modified by controlling its oxidation process in order to prepare porous TiC-TiO2 shell-core composite, which was used as the support for anode electrocatalyst in proton exchange membrane water electrolyzer. Through XRD,BET and TEM characterization methods, BET surface area of the modified TiC was increased by more than 2 times and a multiple phase structure was formed. Cyclic voltammograms （CVs） reveals that the peak current density at 1.5 V vs. SCE on the Ir/TiC is about five times of that on the unsupported Ir black catalyst, and one on Ir/（TiC-TiO2） （the modified TiC） is about six times of that on Ir/TiC. It is obvious that the processed TiC （TiC-TiO2 composite） is better for dispersing precious metals and so its catalytic activity is higher for the oxygen evolution reaction （OER）.