Engineering p/n-type heterojunction of CuSe/Cu₂Se via Co incorporation for enhanced CO₂-to-Ethanol electroconversion

Designing good p/n heterojunctions is of great interest in the pursuit of efficient multi‑carbon product generation through CO₂ reduction reaction (CO₂RR). Herein, a Co-doped CuSe/Cu₂Se p/n-type heterostructure (p/n-CuSe/Cu₂Se-Co) was fabricated, which induces interfacial electronic reconstruction and a strengthened built-in electric field, thereby facilitating charge transfer and enhancing the surface coverage/retention of *CO on Cu-related ensembles, ultimately promoting C-C coupling toward ethanol. Notably, as-prepared p/n-CuSe/Cu₂Se-Co (10.0%) exhibits an ethanol Faradaic efficiency (FE_C2H5OH) of 73.0 ± 1.1% and an ethanol partial current density (j_C2H5OH) of -0.496 ± 0.005 mA cm^-2 in a flow cell at -0.6 V. Additionally, in simulating flue gas condition, it can output 61.2 ± 1.2% of FE_C2H5OH and -0.861 ± 0.003 mA cm^-2 of j_C2H5OH at -0.6 V. This work would provide a feasible reference of advanced p/n-type heterojunction design, promoting the conversion of CO₂-to-ethanol electroconversion.