The role of material defects in the photocatalytic CO2 reduction: Interfacial properties, thermodynamics, kinetics and mechanism

Solar fuels from photocatalysis potentially lower the stress on fossil fuels and therefore subside the environmental pollution. Nevertheless, poor optoelectronic and interface properties of the catalysts lower the CO2 reduction efficiencies, hence a strategy that addresses these fundamental challenges to improve the conversion and selectivity of desired products is needed. To this end, defect-engineering serves as promising direction owing to it’s interlink with band gap, charge recombination, dynamics and also the interface properties. This review comprehensively discusses the details of CO2 conversion ranging from thermodynamics to selectivity on defect-rich photocatalysts. Further, the defect-photocatalysis relationship was unveiled systematically by comparative study of photocatalytic properties between defective and pristine catalysts. Finally, we highlight the challenges and the possible solutions in developing a photocatalyst for solar fuels and hence open new avenues towards the realization of other novel applications. •The critical role of defects in bringing down energy barrier.•The similarities between electrocatalysts and photocatalysts for cocatalyst selection.•The variation of selectivity and reaction pathway attributed to defects.•The importance of synergy of advanced characterizations and theoretical studies.•The potential of photocatalytic CO2 conversion in the future.