BiOBr-Based Catalysts for Photocatalytic Nitrogen Fixation: An Overview from the Perspective of Structural Design

Abstract

Photocatalytic nitrogen reduction (pNRR) offers a carbon-neutral route to ammonia by directly converting solar energy into chemical bonds, presenting a promising alternative to the energy-intensive Haber-Bosch process. However, current progress in pNRR is hindered by the formidable activation barrier of the N≡N triple bond, which severely limits catalytic activity and NH 3 yield. BiOBr-based semiconductors, distinguished by their layered lattice and tunable band structure, exhibit strong visible-light absorption and efficient charge separation, positioning them as compelling platforms for pNRR. This review provides the first comprehensive survey of BiOBr-derived photocatalysts for photocatalytic nitrogen fixation. It begins by introducing the fundamental thermodynamics and reaction pathways of pNRR, followed by an analysis of four key modification strategies employed to enhance BiOBr performance. The review critically assessed the reliability of ammonia quantification protocols, highlighting concerns regarding contamination and artefactual sources.Additionally, three advanced in-situ characterization techniques are discussed for their role in elucidating charge-transfer kinetics. By pinpointing current challenges and outlining future research priorities, this review aims to steer academic exploration, inspire innovative catalyst design, and accelerate the translation of BiOBr photocatalysis toward sustainable, modular ammonia production.