Transient thermal shock induced radial gradient Cu+-Ov-Ce3+/Ce4+ boosted CO2 electroreduction to C2 products

Electrocatalytic CO2 reduction (CO2RR) toward multi-carbon compounds is a challenging but meaningful route for carbon cycling. Copper-based catalysts are the most promising candidate for C2+ generation due to their unique C–C coupling activity, yet the in situ reduction from Cu+ to Cu0 under cathodic potentials causes the catalyst deactivation. Herein, we develop a transient thermal shock strategy to embed Cu+ species into CeO2 lattices, constructing a CuOx/CuCeOx catalyst with a radial gradient Cu+-Ov-Ce3+/Ce4+ structure. Depth-profiling X-ray photoelectron spectroscopy (XPS)and density functional theory (DFT) calculations reveal that mismatched metal/oxygen diffusion kinetics drive continuous electron transfer from surface Cu+ to bulk Ce3+/Ce4+ via oxygen vacancies (Ov), forming a dynamic “self-sacrificial” structure to preserve surface Cu+ states. In CO2-saturated 0.1 M KHCO3, the optimized CuOx/CuCeOx-10 achieves a high C2 Faradaic efficiency (FE) of 85.8 % at −1.4 V vs. RHE. In situ attenuated total reflection surface-enhanced infrared adsorption spectroscopy (ATR-SEIRAS) identifies the key intermediates of C2 are *OCCO and *OCCOH, while DFT reveals a drastic reduction of C–C coupling barrier from 0.842 to 0.274 eV. This work demonstrates kinetically tailored metal-support interactions, enabling oxidation-state control for pathway-selective catalysis.