Reconfiguring Electronic Structures via Synergistic Dual Heterojunctions for Selective CO2 Electroreduction

Electrochemical CO₂ reduction reaction (CO₂RR) is a promising approach for sustainable production of chemicals and fuels, but faces challenges such as low product selectivity and competition from the hydrogen evolution reaction. Herein, an advanced dual heterojunctions catalyst was constructed by integrating hydrogen-bonded organic frameworks (HOFs)-derived two-dimensional (2D) porous N-doped carbon (NC) with copper (Cu) nanoparticles and cerium dioxide (CeO 2 ) nanoparticles, which simultaneously optimized the electronic structure and local reaction environment. The as-synthesized Cu-CeO 2 /NC-1 catalyst integrated p-n heterojunction and Mott-Schottky heterojunction, which synergistically facilitated efficient electron transfer while modulating the adsorption energetics of key reaction intermediates, thereby significantly enhancing the intrinsic catalytic activity. The catalyst exhibited outstanding electrocatalytic performance, achieving a high CO Faradaic efficiency of 96.26% at -0.9 V RHE , demonstrating excellent operational stability over 60 hours of continuous electrolysis. Experimental and density-functional theory calculations demonstrated that the formation of dual heterojunctions triggers charge redistribution and the formation of a built-in electric field at the interface, which enhanced the adsorption and activation of CO₂ at the interface under low overpotentials. This work not only highlighted the considerable potential of dual heterojunctions architectures for advancing CO₂RR technology, but also provided fundamental insights of interfacial synergy in heterostructured electrocatalysts.