Dimensionality-Driven Electronic Modulation at Metal-Perovskite Interfaces for Electrochemical CO₂ Reduction

Electrochemical CO₂ reduction reaction (CO₂RR) offers a sustainable approach for converting CO₂ into value-added chemicals; however, its practical implementation remains limited by high overpotentials and poor selectivity. Metal-oxide interface engineering has recently emerged as a promising strategy to overcome these limitations. While the modulation of metal-support interactions is well established in gas-phase catalysis, their mechanistic manifestation within electrochemical interfaces remains insufficiently understood. Specifically, the influence of support dimensionality on the local CO₂RR microenvironment has not been addressed. In this study, we systematically investigate the role of support dimensionality by comparing Au nanoparticles (NPs) supported on two-dimensional (2D) Ca₂Nb₃O₁₀ (CNO) and three-dimensional (3D) KCa₂Nb₃O₁₀ (KCNO) perovskite oxides as well-defined model systems. The 2D Au/CNO catalyst demonstrated a marked enhancement in CO₂RR performance, achieving a higher CO Faradaic efficiency (FE) than that of the 3D Au/KCNO catalyst. We revealed that the enhanced activity of Au/CNO is attributed to a higher proportion of partially oxidized Au species (Au^δ+) and improved interfacial electronic polarization of Au on CNO. These findings underscore the importance of the oxide support structure in modulating electronic environments and metal-oxide interactions, providing new insights for the rational design of efficient CO₂RR catalysts.