Critical Aspects of Metal-Organic Framework-Based Materials for Solar-Driven CO 2 Reduction into Valuable Fuels

Photoreduction of CO into value-added fuels is one of the most promising strategies for tackling the energy crisis and mitigating the "greenhouse effect." Recently, metal-organic frameworks (MOFs) have been widely investigated in the field of CO photoreduction owing to their high CO uptake and adjustable functional groups. The fundamental factors and state-of-the-art advancements in MOFs for photocatalytic CO reduction are summarized from the critical perspectives of light absorption, carrier dynamics, adsorption/activation, and reaction on the surface of photocatalysts, which are the three main critical aspects for CO photoreduction and determine the overall photocatalytic efficiency. In view of the merits of porous materials, recent progress of three other types of porous materials are also briefly summarized, namely zeolite-based, covalent-organic frameworks based (COFs-based), and porous semiconductor or organic polymer based photocatalysts. The remarkable performance of these porous materials for solar-driven CO reduction systems is highlighted. Finally, challenges and opportunities of porous materials for photocatalytic CO reduction are presented, aiming to provide a new viewpoint for improving the overall photocatalytic CO reduction efficiency with porous materials.