Enhancing Oxygen Reduction Reaction on Mn-Doped ZnO Catalysts: Structural, Electronic, and Mechanistic Insights for Selective Peroxide Production

Abstract In this work, we investigate manganese-doped ZnO catalysts for the oxygen reduction reaction (ORR) in alkaline media, combining structural characterization, electrochemical analysis, and density functional theory (DFT) calculations. XRD confirms that Mn doping preserves the wurtzite ZnO structure while inducing lattice distortions and vibrational shifts indicative of manganese incorporation. XPS analysis reveals that Mn³⁺ is the dominant surface species, which is confirmed by x-ray absorption and emission spectroscopic measurements. Electrochemically, Mn-doped ZnO exhibits enhanced catalytic performance, with increased limiting current density and slight improvements in onset potential compared to pure ZnO. DFT calculations indicate that, while the overall thermodynamics of peroxide formation remain similar, the incorporation of Mn significantly stabilizes the *–OOH intermediate, thereby reducing the energy requirement for this key step. Together, these findings demonstrate that manganese doping improves ORR activity by modifying the electronic structure and enhancing reaction kinetics, offering valuable insights for the design of efficient ZnO-based electrocatalysts for selective H₂O₂ production.