Self-assembled perylene diimide based supramolecular heterojunction with Bi2WO6 for efficient visible-light-driven photocatalysis

Bi2WO6 photocatalyst was hybridized with perylene diimide (PDI) via a facile water bath heating method, the composites photocatalytic oxidation of phenol and water decomposition to produce oxygen are simulated under visible light. It was found that the Bi2WO6/PDI composite shows the higher visible light degradation rate towards phenol than self-assembled PDI and Bi2WO6. What’s more, it simultaneously exhibits an enhanced oxygen production rate, which is 2 times than that of the pure self-assembled PDI. In the photocatalytic process of Bi2WO6/PDI composites under visible light irradiation, the position of conduction band and valence band between Bi2WO6 and PDI are beneficial to realize photogenerated carriers separation. In this work, we synthesized Bi2WO6/PDI heterojunction which is the same as most of the reported n-n type heterojunction photocatalysts, the CB and the VB levels of one are higher than the corresponding levels of the another semiconductor. A new inorganic and organic composite n-n type heterojunction was form to explain the mechanism of photocatalytic activity enhancement. Self-assembled PDI and Bi2WO6 surface hybridization to promote the separation of photogenerated carriers, electrons in the LUMO orbit of PDI are injected into the conduction band of the Bi2WO6, produced a superoxide radical-based visible light degradation activity.