Interfacial Interaction of Ag-MnOx Heterostructure for Efficient CO2 Electroreduction to CO and Aqueous Zn-CO2 Batteries

Abstract

Electrocatalytic CO2 reduction reaction (CO2RR) into valuable chemicals is an appealing way to ease the energy and environmental crises, but the development of efficient catalysts remains challenging. Herein, we reported a novel Ag-MnOx heterostructural catalyst and its high activity for CO2RR to CO. The obtained Ag-MnOx exhibits a CO Faraday efficiency (FECO) of up to 97.5% at −0.8 V vs reversible hydrogen electrode (RHE) and especially maintained a FECO above 90% within a broad potential window of 500 mV (−0.6 ~ −1.1 V vs. RHE). In addition, the CO₂RR performance was optimized using a flow cell, and Ag-MnOx catalyst reached a total current density of −255 mA cm-2 at −2.0 V vs. RHE. Our designed in-situ experiments and density functional theory (DFT) calculations unveil that the heterojunction interface formed between O-defective-rich MnOx and active Ag enhances CO2 adsorption and activation and simultaneously stabilizes the *COOH intermediate, thus leading to its superior catalytic performance. Furthermore, the Ag-MnOx catalyst used as cathode to assemble Zn-CO2 cell exhibits an ultimate power density of 13.63 mW cm−2 and rechargeable time over 65 h.