Metal halide perovskites for CO2 photoreduction: recent advances and future perspectives

CO2 emission has inarguably become one of the greatest challenges ever faced by mankind since industrial revolution. Techniques aiming at capture, storage and utilization of CO2 have attracted tremendous interest from both industry and academia. Thermal, electrical and photo-catalytic conversion of CO2 to value-added chemicals and fuels is the most well-known approach for CO2 utilization. In particular, photocatalytic reduction of CO2 (CO2PR) directly employs solar energy as the driving force to activate CO2, yielding various products including CO, CH4 and C2+ hydrocarbons. CO2PR, which mimics photosynthesis occurring in nature, is also regarded as “artificial photosynthesis” and is believed to be a promising approach toward carbon neutral economy. Recently, metal halide perovskites (MHPs) have emerged as potential photocatalysts for CO2PR, owing to their flexible structures and excellent photoelectronic properties. This review presents a comprehensive overview of state-of-the-art developments in MHP-based catalysts for CO2PR. Firstly, the crystal structures and photoelectric properties of MHPs are reviewed in detail, as they are the key factors determining CO2PR catalytic performance. Secondly, design strategies to promote the catalytic efficiency of CO2PR to CO conversion for both lead-based and lead-free MHPs are discussed, including morphological modifications, co-catalyst modifications, ion doping and crystal plane modifications. Thirdly, this review addresses MHP-based CO2PR to CH4 and C2+ products, with special emphasis on approaches adopted to promote specific product selectivity. Lastly, our perspectives and opinions are given on current research challenges and future directions for CO2PR, which we consider are critical for its industrialization.