Metal–metal oxide hybrid catalysts for electrocatalytic CO2 reduction reaction

Electrocatalytic CO2 reduction is emerging as a promising technology to address anthropogenic carbon emissions, with the searching of effective catalysts being the primary barrier toward industrial implementation. This review starts from the long-standing debates over the role of subsurface oxygen and positively charged metal sites (Mδ+) within oxide-derived catalysts. Thereafter, we focus on the strategy of constructing metal–metal oxide hybrid catalysts, which is enriched with M1–O–M2 heterojunctions that capable of maintaining a positive valence state of active sites and improving CO2 reduction performance. Specifically, advances in metal–metal oxide hybrid catalysts for CO2-to-C1 conversions are overviewed for selective CO, formate, or CH4 production, respectively. Thereafter, we summarize the interfacial engineering approaches for Cu/MOx hybrid catalysts aimed at selective C2+ production, including the interfacial boundary density, the morphology effect of MOx support, the choice of MOx, and their interaction manipulation with Cu sites. This review concludes with an outlook on the challenges and future directions for developing precisely controlled hybrid catalysts with an in-depth understanding of structure–performance relationship. Continued interdisciplinary collaborations from materials science, surface chemistry, analytical methodology, and theoretical modeling will be pivotal in overcoming existing challenges and pushing the frontiers of CO2 reduction research.