Enhanced hydrogen evolution reaction performance of alloyed MoS_1.34Se_0.78 with dominant 1T/T' phases

Transition metal chalcogenides (TMCs) with metallic octahedral (1T) and semi-metallic distorted octahedral (1T') phases have demonstrated superior electrocatalytic activity for the hydrogen evolution reaction (HER) compared to their semiconducting trigonal prismatic (2H) counterparts. However, scalable and mild synthetic approaches to stabilize these metastable phases remain a significant challenge. In this study, we report the synthesis of an alloyed MoS_1.34Se_0.78 catalyst via a simple hydrothermal method. Characterization techniques including Raman spectroscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy confirm the presence of a 1T/T' phase-dominated structure. The alloyed catalyst exhibits excellent HER performance, delivering a low overpotential of 108 mV at -10 mA cm^-2 and a small Tafel slope of 55 mV dec^-1. Moreover, the alloyed structure shows strong phase stability under electrochemical conditions. These findings demonstrate a promising strategy for designing efficient and stable TMC-based catalysts for sustainable hydrogen production.