Progress in catalyst exploration for heterogeneous CO2 reduction and utilization: a critical review

Carbon dioxide (CO2) conversion into more valuable chemicals has attracted great research interest in recent years. Compared to homogeneous catalysts, heterogeneous catalysts are advantageous due to their recyclability and the easy separation of products from catalysts. Research has proved that photocatalysis, electrocatalysis and photoelectrocatalysis are able to reduce CO2 to produce a variety of organic compounds such as carbon monoxide, formic acid, methane, etc., which could not only possibly be used to reduce its accumulation in the atmosphere, but could also produce renewable hydrocarbon fuels. In these processes, catalysts play a significant role in the surface reactions, i.e. to decrease kinetic barriers and to increase activities. Although several review articles related to CO2 reduction have already been published in 2009-2014, due to booming studies in the field of materials, heterogeneously catalysed CO2 reduction has sprung up in recent decades. Therefore, it is important to provide a critical review of the recent progress in catalyst exploration for CO2 reduction, while also providing a framework for research prospects and guiding future research directions in laboratories or in industry. Herein, we review the encouraging research accomplishments achieved in the materials field in recent decades, in terms of structure engineering, cocatalyst development and hybrid catalyst system construction for CO2 reduction via photocatalysis, electrocatalysis and photoelectrocatalysis, with a summary of future research directions in the materials field.