A Pulsed Tandem Electrocatalysis Strategy for CO2 Reduction

Electroreduction of CO 2 to value-added C 2 products remains hindered by sluggish C–C coupling kinetics and competing side reactions. Inspired by the tandem catalytic mechanisms of multienzyme systems, we designed a dual-site single-atom nanozyme (DSAN) comprising FeN 4 and FeO 4 sites (FeN 4 –FeO 4 ). Density functional theory (DFT) calculations under constant potential reveal that the FeN 4 site functions as a CO generator, while the FeO 4 site facilitates CO migration, C–C coupling, and subsequent C 2 product formation. To further optimize the catalytic efficiency, we introduced a pulsed electrocatalysis strategy by alternating between zero potential and −0.7 V. This approach dynamically modulates active-site functions: at −0.70 V, CO 2 adsorption and *CH 3 CH 2 OH formation are facilitated, while at 0 V, CO migration and C–C coupling are enhanced due to the spin-state transitions during potential switching. Additionally, the zero potential suppresses excessive hydrogenation of key intermediates, thereby improving CH 3 CH 2 OH selectivity. These findings highlight the synergistic strategy integrating tandem catalysis and pulsed potential control, offering a novel and effective approach for CO 2 -to-C 2 conversion using SAN catalysts.