Achieving high carrier separation over Bi₄O₅I₂ through Ni doping for improved photocatalytic CO₂ reduction

Abstract

Photocatalytic CO2 reduction is considered to be an appealing way of alleviating environmental pollution and energy shortages simultaneously under mild condition. However, the activity is greatly limited by the poor separation of the photogenerated carriers. Ion doping is a feasible strategy to facilitate the charge transfer. In this work, Ni-doped Bi4O5I2 photocatalyst is successfully fabricated using a one-pot hydrothermal method. A few doping levels appear in the energy band of Bi4O5I2 after Ni doping, which are used as springboards for electrons transition, thus promoting photoexcited electrons and holes separation. As a consequence, a remarkably enhanced yield of CO and CH4 (6.2 and 1.9 μmol g-1 h-1) is obtained over the optimized Bi4O5I2-Ni15, which is approximately 2.1 and 3.8 times superior to pure Bi4O5I2, respectively. This work may serve as a model for the subsequent research of Bi-based photocatalysts to implement high-performance CO2 photoreduction.