Recent advances in photocatalytic reduction of CO2 by TiO2– and MOF–based nanocomposites impregnated with metal nanoparticles

A substantial quantity of CO2 is emitted into the environment due to the large-scale consumption of traditional fossil fuels. Visible-light photocatalytic reduction/conversion of CO2 into an array of alternative renewable solar fuels or other value-added chemicals (like methanol, methane, formic acid, and formaldehyde) is regarded as a sustainable and effective option for the remediation of atmospheric carbon pollution. A good number of composites made of titanium dioxide (TiO2) and metal-organic frameworks (MOFs) have attracted considerable attention for the photocatalytic reduction of CO2. This review article has been organized to focus on recent progress in the modification of TiO2 or MOFs with mono-/bi-metallic nanoparticles (NPs) to synergistically improve the charge transfer mechanism and to increase their active sites for efficient reduction of CO2 under visible light. An overview is offered to describe the fundamental principles of mono/bimetallic doped TiO2 versus MOF-based nanocophotocatalysts along with an evaluation of their performance metrics such as depletion rate and energy cost during the photocatalytic process. Moreover, the challenges and opportunities associated with photocatalytic techniques for CO2 conversion have been discussed to inspire further research in this field.