Breaking the scaling relationship via lattice expansion of Ag for CO₂ electroreduction over a wide potential window

The achievement of excellent catalytic activity for electricity-driven CO2 reduction over a wide potential window is significant for the mature applications. However, the efficient potential range is always limited by the dilemma in CO2 activation and product desorption at different potentials, due to the scaling relationships of adsorption energy. Herein, we developed a nanostructured Ag-CO3 electrocatalyst featuring metallic Ag with Ag(220) orientation on the surface and Ag2CO3 beneath. The interactions between Ag and Ag2CO3 lead to lattice expansion on the surface of Ag, resulting in electron localization and accordingly enhanced CO2 activation to *COOH on Ag. Furthermore, this lattice expansion induces a change in the *CO adsorption geometry from a bridge mode to a linear mode, which compensates the promotion effect of electron localization on *CO adsorption energy. As a result, the scaling relationship between *COOH and *CO adsorption energy was disrupted, leading to enhanced *COOH adsorption and inferior *CO adsorption. Consequently, the Ag-CO3 catalyst exhibited a high FECO (>80%) over a robust potential window of -0.8 to -1.8 V (vs. RHE), with a maximum FECO of 95% at -1.2 V (vs. RHE). The mechanism described herein offers a universal design principle for the development of high-efficiency CO2 electroreduction catalysts that operate effectively within a broad potential range.