Dimension-engineered gold heterostructures with transition metal dichalcogenide for efficient overall water splitting

Metallic 1T' phase two-dimensional (2D) MoS₂ is regarded as one of the most promising transition metal chalcogenide catalysts for hydrogen evolution reaction (HER). However, the poor oxygen evolution reaction (OER) performance of 1T' MoS₂ makes it challenging to use as a bi-functional catalyst for water splitting. Here, we compare the bi-functional electrocatalytic properties of gold heterostructures with 1T' MoS₂ consisting of 4 nm thick 2D Au nanosheets (few layer goldene, FG), 20 nm thick quasi-2D Au nanoplatelets (Au plate) and 250 nm thick Au nanoparticles (Au NPs). Our findings reveal that MoS₂-FG and MoS₂-Au plate 2D heterostructures, characterized by a high density of low-coordinated Au atoms, induce significant strain within the MoS₂ crystal lattice. This strain contributes to the exceptional bi-functional electrocatalytic performance for both HER/OER activities. By leveraging the nanoscale structure of Au and its synergistic interaction with MoS₂, we demonstrate the development of highly efficient, device-ready catalysts, offering significant potential for advancing renewable energy technologies.