Binder-free Mn₂O₃–MoS₂ hybrid composites (HCs) were fabricated using a room-temperature kinetic spray process under low-pressure conditions with various weight ratios of Mn₂O₃–MoS₂ (1:1, 1:2, and 1:4). The effect of the composition ratio on the electrocatalytic activity of Mn₂O₃–MoS₂ HCs toward the oxygen evolution reaction (OER) in an alkaline medium was investigated. The deposited MoS2 exhibits microrods (MRs) morphology, while pure Mn2O3 exhibits nanoflakes (NFs) morphology. The Mn₂O₃–MoS₂ HCs exhibited NFs-decorated MR morphology. Multilayer heterostructure morphology significantly improves the interfacial synergy between various electroactive species that were verified using various spectroscopic techniques such as micro-Raman and X-ray photoemission spectra. As the MoS₂ content in the Mn₂O₃–MoS₂ HCs increased, the
interfacial charge transfer kinetics associated with the reduction in the oxidation barrier potential improved. The Mn₂O₃–MoS₂ HCs with a 1:4 ratio demonstrated the optimum combination for OER with the smallest overpotential of 290 mV @10 mA cm⁻² and Tafel slope of 41 mV dec⁻¹. The long-term OER stability of the fabricated electrocatalysts was verified using chronopotentiometry techniques for 50 h at 50 mA cm⁻²