Fe(Ⅲ)/rGO/Bi_(2)MoO_(6)复合光催化剂制备及光催化芬顿协同降解苯酚

Fe(Ⅲ)/rGO/Bi_(2)MoO_(6) Composite Photocatalyst Preparation and Phenol Degradation by Photocatalytic Fenton Synergy

光催化–芬顿技术耦合可高效降解有机污染物。本研究采用溶剂热法制备了Fe(Ⅲ)掺杂rGO/Bi_(2)MoO_(6)复合催化剂(Fe(Ⅲ)/rGO/Bi_(2)MoO_(6)),通过外加H_(2)O_(2)构建了光催化–芬顿协同体系,可见光照射3 h后对苯酚的降解率(82%)远高于单独光催化(18%)或芬顿反应(48%),进一步优化条件对苯酚可实现完全降解。这主要是通过Fe得失电子实现价态的转变,并以此作为桥梁实现光催化–芬顿的协同作用。同时石墨烯的优异导电性能不仅克服了光催化中光生电子空穴难以分离的问题,而且促进了Fe^(3+)/Fe^(2+)的循环反应,促使芬顿反应产生更多的羟基自由基(·OH),进一步提高了苯酚的降解效率。实验考察了Fe(Ⅲ)含量、催化剂投加量、H_(2)O_(2)含量以及pH等因素对协同降解效果的影响。淬灭实验证明·OH是协同降解体系中最主要的活性物种,·O_(2)^(–)和h^(+)对降解活性也会产生一定的影响,结合实验结果提出了Fe(Ⅲ)/rGO/Bi_(2)MoO_(6)光催化–芬顿协同降解苯酚的机理。

The photocatalysis-Fenton technology coupling can efficiently degrade organic pollutants.In this study,Fe(Ⅲ)-doped rGO/Bi_(2)MoO_(6) composite catalyst(Fe(Ⅲ)/rGO/Bi_(2)MoO_(6))was prepared by solvothermal method,and the photocatalysis-Fenton synergy system was constructed by adding H_(2)O_(2).The phenol degradation activity under 3 h visible light irradation is 82%,much higher than that of photocatalysis alone(18%)or renton reaction(48%),and further optimization can achieve full degration of phenol.This can be mainly attributed to the transformation of the valence state through the gain and loss of Fe electrons,which serves as a bridge to realize the photocatalysis-Fenton synergy.Meanwhile,the excellent electrical conductivity of graphene overcomes the difficulty of separating photo-generated electron holes in photocatalysis,and promotes the cyclic reaction of Fe^(3+)/Fe^(2+),and then accelerates the Fenton reaction to produce more free hydroxyl groups(·OH),which further improves the degradation efficiency.Effects of Fe(Ⅲ)content,catalyst dosage,H_(2)O_(2) content,and pH on the synergy degradation performance were investigated.The quenching experiment proves that ·OH is one of the main active species in the degradation system,while·O_(2)_(-) and H^(+) also have a certain effect on the degradation activity.The mechanism of Fe(Ⅲ)/rGO/Bi_(2)MoO_(6) photocatalysis-Fenton synergy degradation is also proposed based on the present experimental results.