Grain-Boundary-Engineered La₂CuO₄ Perovskite Nanobamboos for Efficient CO₂ Reduction Reaction

Electroreduction of carbon dioxide (CO₂RR) has been regarded as a promising approach to realize the production of useful fuels and to decrease greenhouse gas levels simultaneously, where high-efficiency catalysts are required. Herein, we report La₂CuO₄ nanobamboo (La₂CuO₄ NBs) perovskite with rich twin boundaries showing a high Faraday efficiency (FE) of 60% toward ethylene (C₂H₄), whereas bulk La₂CuO₄ exhibits a FE_CO of 91%. X-ray absorption spectroscopy (XAS) reveals that the Cu in La₂CuO₄ NBs is in the Cu²⁺ state, and no obvious change can be observed during the catalytic process, as monitored by in situ XAS. Density functional theory calculations reveal that the superior FE_C of La₂CuO₄ NBs originates from the active (113) surfaces with intrinsic strain. The formation of gap states annihilates the electron transfer barrier of C-C coupling, resulting in the high FE_C. This work provides a new perspective for developing efficient perovskite catalysts via grain boundary engineering.