One-Step Hydrothermal Synthesis of Phase-Engineered MoS₂/MoO₃ Electrocatalysts for Hydrogen Evolution Reaction

The development of suitable approaches for the synthesis ultrathin transition-metal dichalcogenide (TMD) catalysts is required to engineer phases, intercoupling between different in-plane defects, and edges hence maximize their catalytic performance hydrogen production. In this work, we report a simple one-step hydrothermal approach three-dimensional (3D) network self-assembled metallic MoS2/MoO3 nanosheets, using α-MoO3 thiourea (TU) as Mo S precursors, respectively. A systematic structural/property relationship study, while varying precursors’ molar concentration ratios (TU/MoO3) reaction temperatures (TR), revealed kinetically controlled regime, in synthesis, that enabled formation branched nanosheets with highest content ∼47 % reproducible manner. Importantly, work established addition rich MoS2 phase (1T), electronically coupled interfaces MoO3 nanodomains, profusion active sites, tuned electrical conductivity significantly contributed evolution (HER)-catalytic activity, affording low overpotential 210 mV (with respect reversible electrode) at current density 10 mA/cm2, small Tafel slope ∼50 mV/dec, high stability. Overall, demonstrated controllable method rational design 3D 1T-MoS2 yield, simultaneous incorporation MoO3/MoS2 heterointerfaces, sulfur vacancies, conductivity, which are highly beneficial clean energy conversion applications can potentially be expanded other two-dimensional TMD materials.