Manganese Doped-Nitrogenated Carbon as an Efficient Catalyst for Acidic Electrocatalytic Reduction of CO2.

ABSTRACT

Renewable electricity-driven CO2 electroreduction to value-added chemicals is a feasible approach to alleviate both environmental and energy issues. However, CO2 reduction reaction (CO2RR) systems in alkaline electrolytes are constrained by intrinsic limitations such as salt accumulation that impede further industrialization. Herein, an atomically dispersed Mn doped-nitrogen carbon (AD MnNC) catalyst is developed to electrochemically reduce CO2 to CO in both neutral and acidic media. Benefiting from well-dispersed MnNx sites, the maximum CO Faradaic efficiency (FECO) reaches ≈100% at -0.73 V versus reversible hydrogen electrode (RHE) with CO current density (JCO) of 20.4 mA cm-2 in neutral 0.5 m KHCO3. Due to diminished *H adsorption, AD MnNC achieves a FECO of 85.3% at pH 2.0, effectively suppressing the hydrogen evolution reaction (HER) in an acidic electrolyte. The mechanistic study reveals that AD MnNC accelerates the production of *COOH intermediates through a proton-coupled electron transfer (PCET) pathway and thus promotes CO formation.