From molecular metal complex to metal-organic framework: The CO2 reduction photocatalysts with clear and tunable structure

Photocatalytic reduction of CO2 to high value-added productions is considered as a green and sustainable approach to reducing excessive CO2 emissions. Molecular metal complexes (MMCs) and metal-organic frameworks (MOFs) are wildly studied as potential photocatalysts for CO2 reduction reaction (CO2RR) due to their clear and tunable structures. In this review, we summarize the photochemical CO2RR based on both homogeneous MMCs and heterogeneous MOFs and discuss molecular engineering approaches and key advances in this field. Discussing the photocatalytic CO2RR properties of MMCs and MOFs is beneficial to elucidating the structure-activity relationship and reaction mechanism in the photocatalytic process. These discussions will provide scientific and technical guidance for the rational design and development of more creative systems for photocatalytic CO2RR. In addition, challenges and prospects for future research of photocatalytic CO2RR based on these coordination compounds are proposed.