Recent progress and perspectives in heterogeneous photocatalytic CO2 reduction through a solid–gas mode

The conversion of CO2 into valuable chemical feedstock through photocatalysis is considered as an effective strategy to mitigate global warming and energy-supply problems. The key challenge in CO2 photoreduction is to design and synthesize powerful photocatalysts with superior advantages in absorbing visible-light, CO2 enrichment/activation, and electron-coupled proton transition ability to facilitate the photoreduction process. During the past decades, various kinds of photocatalysts have been designed and explored for CO2 photoreduction, and more and more achievements about CO2 photoreduction have been made. However, the exploration of CO2 photoreduction in the solid–gas mode is still in its infancy and the performance of reported photocatalysts are far from meeting the demand of practical applications. This review will summarize the reported literatures about CO2 photoreduction via the solid–gas mode including the summary of their performances, reaction conditions and mechanistic pathway, etc. Besides, multiple strategies like experimental evidences and theoretical studies reported for the enhancement of CO2 photoreduction performance have also been outlined and discussed. Moreover, we have proposed a brief perspective on the challenges about further development of CO2 photoreduction in the solid–gas mode and hope to provide new insights for scientists in this field.