Phase control of MoWS2 nanostructures via oxalic acid-assisted electron injection: From molybdenum disulfide to tungsten disulfide

Abstract

Metallic-phase molybdenum disulfide (1T-MoS₂) and tungsten disulfide (1T-WS₂) have attracted great attention due to their excellent performance in the field of electrochemical hydrogen evolution catalysis. Recent studies have demonstrated that reducing the potential barrier of lattice distortion and injecting electrons into materials are the keys to synthesizing 1T phase transition metal dichalcogenides (1T-TMDs) materials with long-term stability. Here, a novel synthesis strategy for 1T-TMDs was proposed. With the assistance of oxalic acid, the continuous synthesis from semiconductor-phase (2H) MoS₂ to 1T-MoWS₂ and then to 2H-WS₂ was achieved by changing the proportion of precursors. The 1T-phase of MoWS₂ has a proportion of 74.36 %. Phase transformation mechanism analysis shows that the construction of the ternary structure reduces the lattice distortion barrier, and oxalic acid directly injects electrons into the ternary structure, providing a driving force for the formation and stabilization of the 1T-phase. Compared with the 2H-phase, the 1T-phase MoWS₂ has significantly optimized electrochemical catalytic performance. Density functional calculations and transient absorption results revealed that the origin of the efficient catalytic performance of 1T-phase MoWS₂, with special electronic structure being the main reason. This study provides a new strategy for the structural design and synthesis of high-efficiency 1T phase catalysts