Recent progresses on improving CO2 adsorption and proton production for enhancing efficiency of photocatalytic CO2 reduction by H2O

Photocatalytically reducing CO2 by H2O into valuable carbon-containing chemicals is one of the greatest concerns for both scientific and industrial communities, due to its great potential in solving energy and environmental problems. However, the photocatalytic reduction efficiency is still much lower than the need of large-scale applications. Abilities of photocatalysts in adsorbing CO2 and splitting H2O to produce protons are crucial factors determining the photocatalytic reduction efficiency. Significant research efforts have been devoted to addressing the issues on CO2 adsorption and proton production. The present review discusses the recent progresses in improving CO2 adsorption and proton production on photocatalysts for increasing the photocatalytic reduction efficiency. Future research opportunities and challenges are also discussed. It is hoped that the present review can stimulate more deep insights on adsorption of CO2 and production of proton for increasing the photocatalytic reduction efficiency. [Display omitted] •the structural and electronic properties of CO2δ– are essential for the selectivity and yield of carbon-containing products.•Photocatalytic reduction efficiency is directly influenced by the amount of proton involved in CO2 reduction.•Coating carbon layers on the photocatalyst can not only improve the CO2 adsorption but also promote the proton capture.•The photocatalytic reduction designs for CO2 reduction are discussed in detail.