Molybdenum-Doped Manganese Oxide as a Highly Efficient and Economical Water Oxidation Catalyst

The development of efficient and noble-metal-free electrocatalysts for the challenging oxygen evolution reaction (OER) is crucial for sustainable energy solutions. In this work, a facile co-precipitation method, followed by thermal postsynthetic treatment in N2/air, was developed to synthesize molybdenum-doped α-Mn2O3 materials (Mn2O3:1.72%Mo, Mn2O3:2.64%Mo, Mn2O3:32.23%Mo, and Mn2O3:49.67%Mo) as low-cost water-oxidizing electrocatalysts. Powder X-ray diffraction (PXRD), extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM) investigations showed the presence of strong distortions in the molybdenum-doped α-Mn2O3 host lattice (Mn2O3:2.64%Mo) and an average oxidation state of Mn2.8+. Several test assays demonstrated that these structural features significantly promote the OER activity. Mn2O3:2.64%Mo was found to exhibit very good activity among the series in cerium ammonium nitrate (CAN)-assisted water oxidation ...