Boosting time efficiency and CO2-to-C2+ conversion in pulsed CO2 electroreduction over Pd-modified Cu2O catalyst

Pulsed electrocatalytic CO 2 reduction reaction (p-CO 2 RR) on copper-based catalysts can dynamically stabilize active Cu + sites and enrich surface *OH, enabling sustained CO 2 -to-C 2+ conversion. However, its practical application is still constrained by: 1) low time efficiency caused by both the inherent instability of Cu + during cathodic polarization and the sluggish re-oxidation of Cu 0 to Cu + , and 2) inadequate CO 2 -to-C 2+ conversion efficiency caused by the insufficient *OH coverage. To address these challenges, a Pd-modified Cu 2 O catalyst (Pd-Cu 2 O) with strong Pd-Cu electron interaction is designed. In situ experiments and theoretical studies reveal that Pd induces stable electron-deficient Cu + /Cu 0 sites, which effectively suppressing Cu + reduction during the cathodic phase and promoting Cu + regeneration during anodic phase, thus shortening the required oxidation duration. Concurrently, Pd accelerates water dissociation and enhances *OH coverage, which facilitates *CO adsorption and enhances C-C coupling. As a result, Pd-Cu 2 O achieves a Faradaic efficiency for C 2+ of 79.8 % with stable operation for over 50 h, and the time efficiency exceeding 87 %, outperforming most reported p-CO 2 RR catalysts. This work highlights the importance of rational catalyst design via electronic structure regulation for enhancing the time efficiency and C 2+ production performance for p-CO 2 RR, paving the way for efficient CO 2 -to-C 2+ conversion and practical applications.