Insights into the metal–organic framework-based materials for photocatalytic CO2 reduction

The increasing environmental pollution and energy scarcity caused by the massive burning of fossil fuels have become the two major problems and the most controversial issues. The use of sunlight-driven composites to convert carbon dioxide (CO₂) into other value-added compounds is a promising strategy that plays a pivotal role in alleviating energy crisis and solving environmental issues. Metal-organic frameworks (MOFs) are widely employed in photoreductive CO₂ systems because of their tunable structures, excellent photocatalytic activity and abundant active sites. During the CO₂ reduction reaction, the reduction products obtained from different reduction pathways are distinct duo to the involvement of multiple intermediates and complex reduction routes, which makes it more fascinating to rationally regulate the MOF composites to target the generation of different carbonaceous compounds. In this paper, we summarised the latest results of photocatalytic CO₂ reduction by MOF-based composites and introduced the synthesis methods and morphological characteristics of MOF materials. Moreover, the adsorption state of CO₂ molecules on the photocatalysts and the possible pathways experienced by the formation of the final products are outlined. Finally, the development prospects and still existing problems of the CO₂ reduction system catalysed by MOF photocatalysts were presented. We hope that this paper can provide valuable assistance to researchers in the rational modification and design of MOF-based photocatalysts.