g-C3N4/rGO杂化催化剂的简易合成及其对罗丹明B的光催化降解作用

在空气中直接加热三聚氰胺和氧化石墨烯(GO)的混合物制备了g-C3N4/rGO杂化催化剂.实验结果表明，混合物中的g-C3N4保留了石墨型氮化碳原始的特征结构， g-C3N4和还原的氧化石墨烯(rGO)之间的异质结主要通过π-π作用构筑.当原料中三聚氰胺/GO的质量比是800/1时，所得催化剂对罗丹明B的催化作用最强，其一阶动力学常数是纯g-C3N4的2.6倍.这种强化作用主要是由于rGO促进了光生电子-空穴对的分离.此外， g-C3N4/rGO还表现出显著的pH值敏感特性，催化降解速率随pH的降低而增加.当pH =1.98时，其一阶动力学常数是纯g-C3N4的8.6倍.这是由于酸性条件下质子(H+)消耗掉光生电子，促进了空穴对罗丹明B的氧化作用，其中rGO充当了一个快速的光生电子转移平台.

Simple synthesis of g-C3N4/rGO hybrid catalyst for the photocatalytic degradation of rhodamine B

A hybrid catalyst of g-C3N4 (graphitic carbon nitride)/rGO (reduced graphene oxide) was prepared by directly heating a mixture of melamine and GO in air. g-C3N4 in the hybrid retained the structure of pristine g-C3N4, and the heterojunction between g-C3N4 and rGO was formed by π-π interaction. The highest photocatalytic efficiency for the degradation of rhodamine B (RhB) was with the mela-mine/GO mass ratio of 800/1, with a first order rate constant 2.6 times that of pristine g-C3N4. The enhanced photocatalytic activity was assigned to the rGO-promoted separation of photo-generated electron (e–)-hole (h+) pairs. In addition, the photocatalytic activity of g-C3N4/rGO was pH sensitive with a much increased photodegrading rate at low pH values. The first order rate constant was 8.6 times that of pristine g-C3N4 at pH = 1.98. The pH sensitive behavior resulted from the promoted oxidation of h+ with RhB by the consumption of e? with the reaction of proton (H+) in which rGO acted as a good platform for transferring e– through its atomic sheets.