The development of efficient Cu-based heterogeneous catalysts for CO₂ hydrogenation to methanol has been an appealing subject. Inspired by the concept of inverse catalysts, a series of La₂O₂CO₃/Cu nanorod composites with varying Cu contents (denoted as LOC/Cu-x, where x stands for the mass ratio of La and Cu in the catalysts) were prepared by combining coprecipitation and calcination processes. Remarkable composition-dependence of catalytic activity and selectivity were observed when different LOC/Cu-x (x = 0.1, 0.2, 0.5, 1, 3 and 5) were used to catalyze the CO₂ hydrogenation. The predominant product shifted from methane to methanol with the increasing Cu content. The highest reaction rate (13.3 mmol·g_Cu⁻¹·h⁻¹) and methanol selectivity (85.5%) were achieved when LOC/Cu-1 was tested at 200 °C. The LOC was not active for the reaction, while the Cu itself displayed poor catalytic performance. The Cu–LOC interactions significantly affected the nature of the catalysts, including mutual electron transfer, crystal structure, morphology, porosity, surface Cu valence and capability of adsorbing the reactant gases, etc., which account for the outstanding behavior of the LOC/Cu-1 catalyst. This work provides a new strategy for the design and optimization of Cu-based catalysts.

Electroreduction of small molecules such as CO₂, N₂, and NO₃⁻ is one of the promising routes to produce sustainable chemicals and fuels and store renewable energy, which could contribute to our carbon neutrality goal. Emerging multicomponent electrocatalysts, integrating the advantages of individual components of catalysts, are of great importance to achieve efficient electroreduction of small molecules via activation of inert bonds and multistep transformation. In this review, some basic issues in the electroreduction of small molecules including CO₂, N₂, and NO₃⁻ are briefly introduced. We then discuss our fundamental understanding of the rule of interaction in multicomponent electrocatalysts, and summarize three models for multicomponent catalysts, including type I, “a non-catalytically active component can activate or protect another catalytic component”; type II, “all catalytic components provide active intermediates for electrochemical conversion”; and type III, “one component provides the substrate for the other through conversion or adsorption”. Additionally, an outlook was considered to highlight the future directions of multicomponent electrocatalysts toward industrial applications.