硼酸金属化合物的制备及其电催化活性

采用电化学沉积法于室温、碱性条件下在氧化铟锡(ITO,Indium Tin Oxide)表面制备了硼酸钴(CoBi)、硼酸镍(NiBi)、硼酸锰(MnBi)、硼酸铑(RhBi)、硼酸钯(PdBi)几种无定形的硼酸金属化合物薄膜,并对其形貌和结构进行表征,结果表明几种薄膜均为无定形结构.将这几种硼酸金属化合物应用于电化学催化水氧化制氧,对比其催化活性,发现CoBi,NiBi,RhBi具有较高的催化性能,而MnBi和PdBi催化活性较低.进一步研究硼酸pH值对CoBi电催化水分解的影响.发现硼酸有利于金属化合物的制备,pH7~11范围内,HBO₃^2-作为质子受体含量逐渐增大,能接受放氧过程产生的质子,促进催化水分解过程的进行.所得催化剂可自我修复,实现循环利用.

Preparation of borate-based metal compounds and their electrocatalytic activities

Borate-based metal compounds thin film such as cobalt-borate(CoBi), nickel-borate(NiBi), manganese-borate(MnBi), rhodium-borate(RhBi) and palladium-borate(PdBi) were prepared on the surface of indium tin oxide(ITO) through electrochemical method at room temperature in alkaline medium. These compounds were amorphous films by morphology and structure characterization. Comparing their catalytic activities in electrocatalytical water splitting for oxygen generation, CoBi, NiBi and RhBi show higher activity than MnBi and PdBi. Further research indicates that borate is beficial for the preparation of borate-based metal compounds, and as a proton acceptor, the concentration of HBO₃^2- rised gradually as pH increases from 7 to 11, HBO₃^2- can accept the proton produced from oxygen evolving process, improving the electrocatalytical water splitting. In addition, the as-synthesized catalysts could be self-repaired and recycled.