Perovskite Paradigm Shift: A Green Revolution with Lead-Free Alternatives in Photocatalytic CO₂ Reduction

Carbon dioxide (CO2), an archetypal greenhouse gas, can be transformed into valuable fuels through photocatalysis, presenting an auspicious avenue for combating global climate change and energy crisis. While halide perovskites have sparked substantial research interest, concerns over lead toxicity have spurred exploration of their lead-free counterparts for CO2 photoreduction. This comprehensive Review navigates through the fundamentals of CO2 reduction, delving into the basic principles, mechanisms, and relevant operando techniques. It then introduces the diverse structures of lead-free halide perovskites (LFHPs), synthesis methodologies, and intrinsic properties that render them suitable for CO2 photoreduction. Subsequently, the Review unfolds their application and modification strategies for light-driven CO2 conversion, highlighting their breakthroughs and shedding light on their potential mechanisms. Finally, the current challenges and strategies to tailor LFHPs for robust photocatalytic CO2 reduction are critically discussed, offering insights for future research in this realm. This Review aims to illuminate the path toward sustainable photocatalysis, bridging knowledge gaps and inspiring innovations for a greener and carbon-neutral tomorrow.