Recent advances in direct gas–solid-phase photocatalytic conversion of CO2 for porous photocatalysts under different CO2 atmospheres

Photocatalytic carbon dioxide (CO2) reduction is a promising strategy to mitigate global warming and supply green fuels and chemicals. However, due to the low CO2 adsorption capacity of the photocatalysts and limited CO2 dissolution, the conversion rate of CO2 and selectivity in the aqueous solution is typically unsatisfactory, which cannot meet the requirements of practical application. This paper reviewed the latest advances in metal–organic frameworks (MOFs)- and polymer-based photocatalysts for the gas–solid conversion of CO2. Various atmospheres are reviewed, including high-purity CO2, diluted CO2, and CO2/O2 mixtures. Due to favorable adsorption and selectivity toward CO2, porous photocatalysts show high efficiency in photocatalysis, even at ultralow CO2 concentration or in the presence of oxygen. In addition, we summarize the challenges in photo-CO2- reduction technology under the gas–solid phase and provide perspectives on the development of multifunctional materials with high CO2 adsorption and photocatalytic conversion performances.