铁辅助光电催化实验及机理研究

Experimental and mechanism study on Fe-assisted photoelectrocatalytic

为了探究铁对光催化、电催化以及光电催化降解水中有机污染物效率的影响以及铁提升光电催化效率的机理,将Co、N、P/TiO_(2)/SiO_(2)/CoFe_(2)O_(4)颗粒作为粒子电极应用于光电催化降解罗丹明B的实验,并对催化反应过程中铁浓度变化进行检测。结果表明,铁的存在可以使光催化、电催化以及光电催化降解罗丹明B的效率显著提高。其中,Fe^(3+)可使光催化反应速率提升290.68%;Fe^(2+)、Fe^(3+)、牺牲阳极法可使电催化反应速率分别提升59.21%、250.94%、162.45%;可使光电催化反应速率分别提升37.38%、536.86%、525.44%。光催化反应中的Fe^(3+)浓度快速下降。分析铁提升光电催化效率的机理主要是Fe^(3+)作为光生电子捕获剂,加速了TiO_(2)上光生电子—空穴的分离,从而产生更多的·OH;Fe^(3+)在阴极可以被还原为Fe^(2+);Fe^(2+)可与光催化或电化学氧化过程中产生的H_(2)O_(2)反应生成·OH。

In order to investigate the effects of Fe on the efficiency of photocatalytic,electrocatalytic,and photoelectrocatalytic degradation of organic pollutants in water,as well as the mechanism by which Fe enhances the photoelectrocatalytic efficiency,Co,N,P/TiO_(2)/SiO_(2)/CoFe_(2)O_(4) particles were used as particle electrodes for the photoelectrocatalytic degradation of Rhodamine B,and the changes in Fe concentration during the catalytic reaction were detected.The results indicate that the presence of Fe can significantly improve the efficiency of photocatalytic,electrocatalytic,and photoelectrocatalytic degradation of Rhodamine B.Among them,Fe^(3+)can increase the photocatalytic reaction rate by 290.68%;Fe^(2+),Fe^(3+),and sacrificial anode methods can increase the electrocatalytic reaction rates by 59.21%,250.94%,and 162.45%,respectively;it can increase the photocatalytic reaction rates by 37.38%,536.86%,and 525.44%,respectively.During the photocatalytic reaction process,the concentration of Fe^(3+)rapidly decreases.The mechanism by which Fe enhances the photoelectrocatalytic efficiency is mainly analyzed as follows:Fe^(3+)acts as a photo-generated electron capture agent,accelerating the separation of photo-generated electrons and holes on TiO_(2),which makes the photocatalytic reaction produce more·OH;Fe^(3+)is reduced to Fe^(2+)at the cathode;Fe^(2+)can react with H_(2)O_(2) generated during photocatalysis or electrochemical oxidation to generate·OH.