Low-temperature coating of Mn<subscript>2</subscript>O<subscript>3</subscript>–MoS<subscript>2</subscript> micro-nano-heterostructure anode as an efficient catalyst for water splitting applications.

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-to-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. [ABSTRACT FROM AUTHOR]