Bismuth‐Based Photocatalysts for Water Remediation: Design Strategies, Mechanisms, and Challenges

Bismuth‐based semiconductors have been widely studied as visible light‐driven photocatalysts for water remediation because of their adjustable electronic structures and good chemical stability. This review summarizes recent progress in the design and modification of bismuth‐based photocatalysts for the removal of organic pollutants in water. Strategies, including oxygen vacancy regulation, defect‐induced band structure adjustment, dual metal doping, and heterojunction construction, are discussed with a focus on how they influence light absorption, charge separation, and reactive oxygen species formation. The integration of bismuth‐based photocatalysts with hybrid processes, such as photoelectrocatalysis, micro and nanobubble‐assisted systems, and photo‐Fenton reactions, is also reviewed, highlighting their roles in lowering reaction barriers, improving mass transfer, and sustaining radical generation. Current challenges related to oxygen vacancy identification under working conditions, reaction mechanism clarification, and reactor scale application in complex water matrices are critically examined. Finally, future research directions are proposed to guide the rational design and practical application of bismuth‐based photocatalytic systems for water environmental remediation.