Synergistic Effect of Dual Electron-Cocatalysts for Enhanced Photocatalytic Activity: rGO as Electron-Transfer Mediator and Fe(III) as Oxygen-Reduction Active Site

For a high-performance cocatalyst-modified photocatalyst, an effective interfacial separation of photogenerated electron from its corresponding holes and its following reduction reaction at the active sites are highly required. However, it is difficult for a single-component cocatalyst to simultaneously realize the crucial functions. In this study, an effective interfacial transfer of photogenerated electrons and its following rapid oxygen-reduction can be easily realized in a dual electron-cocatalyst modified Fe(III)/rGO-TiO2 photocatalyst, where the rGO nanosheets function as an electron-transfer mediator for the effective transfer of photogenerated electrons from the TiO2 surface while the Fe(III) cocatalyst serves as an electron-reduction active site to promote the following interfacial oxygen reduction. In this case, the rGO nanosheets were firstly loaded on the TiO2 nanoparticle surface by a hydrothermal method and then the Fe(III) cocatalyst was further modified on the rGO nanosheets by an impregnation method to prepare the Fe(III)/rGO-TiO2 photocatalyst. It was found that the dual electron-cocatalyst modified Fe(III)/rGO-TiO2 photocatalyst showed an obviously higher photocatalytic performance than the naked TiO2 and single-cocatalyst modified photocatalysts (such as Fe(III)/TiO2 and rGO-TiO2) owing to the synergistic effect of rGO and Fe(III) bi-cocatalysts. The present work can provide some new insights for the smart design of high-efficiency photocatalytic materials.