Revealing the Role of Mn–O Bonds in Electrocatalytic Methanol Oxidation to Value-Added Formate in LaMnO3

Abstract

Understanding the structure–activity relationships in perovskite catalysts is essential for advancing renewable electrochemical energy technologies. This study reports the exceptional performance of LaMnO₃ deposited on nickel foam (NF) electrodes in selective methanol electrooxidation. Experimental analyses reveal that the preferred crystalline facets of LaMnO₃ grown on nickel foams predominantly generate {110} facets, and this facet engineering effectively promotes the adsorption of methanol molecules. Moreover, the electronic structure of the Mn–O bonds on the LaMnO₃ surface has been optimized, resulting in good activity and approximately 100% Faradaic efficiency (FE) at current densities ranging from 100 to 500 mA cm^–2. Notably, the total FE for formate demonstrates durability for up to 10 h at 100 mA cm^–2, with selectivity exceeding 86%. This results in a substantial reduction (∼15.88%) in energy consumption for producing pure hydrogen. In situ studies indicate that the unique structure of LaMnO₃/NF facilitates the formation of high-valent active Mn–O species and stabilizes the crystalline framework through an interfacial Mn–O network. This configuration provides abundant active sites and oxygen sources for converting methanol to formate, establishing a stable and efficient catalytic environment.