Self-Assembled Controllable Cu-Based Perovskite/Calcium Oxide Hybrids with Strong Interfacial Interactions for Enhanced CH4 Electrosynthesis.

Abstract

Cu-based perovskite oxide catalysts show promise for CO2 electromethanation, but suffer from unsatisfactory CH4 selectivity and poor stability. Here, we report self-assembled, controllable Cu-based perovskite/calcium oxide hybrids with strongly interacting interfaces for high-performance CH4 electrosynthesis. As proof-of-concept catalysts, the La2CuO4/(CaO)x (x from 0.2 to 1.2) series has tunable CaO phase concentrations and thus controllable interface sizes. The La2CuO4 and CaO components are intimately connected at the interface, leading to strong interfacial interactions mainly manifested by marked electron transfer from Ca2+ to Cu2+. In CH4 electrosynthesis, their activity and selectivity show a volcano-type dependence on the CaO phase concentrations and are positively correlated with the interface sizes. Among them, the La2CuO4/(CaO)0.8 delivers the optimal activity and selectivity for CH4, together with good stability, much better than those of a physical-mixture counterpart and most reported Cu-based perovskite oxides. Moreover, La2CuO4/(CaO)0.8 stands out as one of the most effective Cu-based catalysts for CH4 electrosynthesis, achieving a high CH4 selectivity of 77.6% at 300 mA cm-2. Our experiments and theoretical calculations highlight the significant role of self-assembly-induced strong interfacial interactions in promoting *CO adsorption/hydrogenation, intensifying resistance to structural degradation, and consequently underpinning the achievement of such optimized performance.