From Carbon Nitrides to COFs: Opportunities and Prospects in Photocatalytic CO₂ Reduction

The continuing increase in atmospheric carbon dioxide (CO₂), a major greenhouse gas and accelerating climate change are driving demand for innovative mitigation strategies. The photocatalytic CO₂ reduction reaction (PCO₂RR) presents a promising and sustainable route to convert CO₂ into useful hydrocarbons and fuels utilizing sunlight, thereby mitigating CO₂ emissions. This review examines the developmental aspects of light-driven CO₂ conversion using organic polymeric photocatalysts, focusing on carbon nitrides (CNs), covalent triazine frameworks (CTFs), and covalent organic frameworks (COFs). These materials are verified to possess great potential for PCO₂RR, because they offer tunable band gaps, large surface areas, efficient light absorption, and remarkable activity and selectivity in photocatalysis. In this review, the comprehensive analysis of photocatalytic materials (e.g., CNs, CTFs, and COFs) are thoroughly discussed, along with their mechanisms, historical advancements, and urgent roles in PCO₂RR. Strategies for enhancing the CO₂ photoreduction efficiency of CNs, CTFs, and COFs are also highlighted. Each organic material brings distinct advantages. The review also addresses critical challenges, such as improving efficiency and managing charge transport dynamics for PCO₂RR. Finally, the review underscores the need to develop scalable CO₂ conversion applications, advance organic photocatalyst material science, and support sustainable energy conversion technologies.