Recent advances on photocatalytic CO2 reduction using CeO2-based photocatalysts: A review

Efforts to combat global warming and energy-related issues involve the solar-driven reduction of CO2 into worthy fuels and substances. However, the stable nature of CO2 demands high energy input for transformation. CO2 reduction using semiconductor materials activated by sunlight is gaining attention for its eco-friendly and economically viable nature. Despite progress, many solar-active catalysts for CO2 photoreduction encounter challenges like low efficiency and uncontrollable selectivity. The commonly used rare earth oxide ceria (CeO2) has low sunlight absorption, necessitating changes such as metal-nonmetal doping oxygen vacancy creation, the addition of co-catalysts, and the development of binary, ternary, Z-scheme, and S-scheme heterostructures to improve its use in visible light. Although there has been considerable research on CeO2 modifications, there is a lack of comprehensive study regarding their characteristics and the precise photochemical reduction mechanisms. This review aims to bridge this gap by thoroughly examining recent breakthroughs in CeO2-based photo reductants for CO2 reduction. It focuses on the synthetic techniques of photocatalysts and CO2 reduction processes, assesses photoactivity enhancement strategies, investigates underlying mechanisms, and addresses the factors influencing CO2 reduction, efficiencies and selectivity. Finally, the review concludes by offering insights into future challenges and prospects, guiding upcoming research toward sustainable and efficient CO2 reduction strategies.