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

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 MnN_x sites, the maximum CO Faradaic efficiency (FE_CO) reaches ≈100% at -0.73 V versus reversible hydrogen electrode (RHE) with CO current density (J_CO) of 20.4 mA cm^-2 in neutral 0.5 m KHCO₃. Due to diminished ^*H adsorption, AD MnNC achieves a FE_CO 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.