Bismuth oxybromide photocatalysts for CO2 reduction: modification methods, bottlenecks, and optimization strategies

Abstract

Bismuth oxybromide (BiOBr), as a typical layered bismuth oxyhalide semiconductor material, has attracted considerable attention from researchers in the energy and environmental fields in recent years due to its suitable band structure, excellent visible light response capability, potential carrier separation advantage brought by the unique layered structure, and environmentally friendly characteristics. It has demonstrated significant research value and broad application potential, particularly in the field of photocatalytic carbon dioxide (CO₂) reduction. However, BiOBr has an inherent defect, characterized by a high recombination rate of photogenerated electron–hole pairs, which prevents the full utilization of the carrier separation advantage of its layered structure and thus limits its catalytic activity for CO₂ reduction. Therefore, the development of efficient modification strategies to optimize the catalytic performance of BiOBr has become a research hotspot in this field. This review systematically discusses BiOBr-based photocatalysts: first, starting from the intrinsic properties of the material, it analyzes the potential advantages and actual shortcomings of BiOBr in photocatalytic CO₂ reduction, laying a foundation for clarifying the subsequent research directions; second, it explains the basic reaction mechanism and product generation path of photocatalytic CO₂ reduction, and summarizes the key factors affecting reaction efficiency and common preparation methods, providing theoretical and technical support for the proposal of modification strategies; on this basis, it comprehensively sorts out the mainstream modification strategies such as crystal structure regulation, morphology optimization, defect engineering construction and heterojunction composite, showing the research progress and technical breakthroughs in this field. Although significant phased achievements have been made in BiOBr-based photocatalysts in the field of CO₂ reduction, they still face practical challenges such as high preparation cost, insufficient material stability, and low precision in product selectivity regulation. By systematically integrating existing research results and in-depth analysis of existing problems, this review aims to provide valuable references for subsequent researchers to further improve the catalytic performance of BiOBr, fully release its potential advantages, and promote its practical application in the field of photocatalytic CO₂ reduction.