Defect engineering of Z-scheme heterojunction catalysts for efficient CO2 photoreduction
Ye Song, Yang Song, Xiang Li, Ruoyu Wang, Shangcong Sun, Qiuqiao Jiang, Haitao Song, Wei Lin, Wei Lin, Wenbin Lin, Wenbin Lin
Abstract
Photocatalytic CO 2 reduction coupled with water oxidation for the generation of valuable hydrocarbons represents a promising solution to address the challenges in sustainable energy production and clean environments. However, the limited efficiency of conventional photocatalysts due to their rapid charge recombination and insufficient visible-light utilization remains a bottleneck. Herein, we report defect-engineered Z-scheme heterojunction catalysts to overcome these challenges. Fe-O v 300/PCN was synthesized via precise control of oxygen vacancies in α-Fe 2 O 3 and integrated with polymeric graphitic carbon nitride (PCN) and showed significantly enhanced photocatalytic activity for CO 2 reduction. Comprehensive characterization by X-ray diffraction, transmission electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy (XPS) revealed robust interfacial electronic coupling and stable structural integrity. Photocatalytic CO 2 reduction tests under visible light irradiation showed a CH 4 production rate of 106 μmol g -1 h - 1 , approximately 12 times that of pristine PCN and significantly higher than benchmark α-Fe 2 O 3 /PCN. Mechanistic investigations by UV–vis diffuse reflectance spectroscopy, electron paramagnetic resonance, and in-situ XPS confirmed the establishment of a direct Z-scheme charge transfer pathway with efficient separation and prolonged carrier lifetimes. This work demonstrates the potential of defect engineering and heterojunction design in advancing CO 2 conversion technologies for sustainable energy production and ensuring clean environments.