Pt Nanoparticles on Vertically Aligned Large-Area MoS<inf>2</inf> Flakes for Selective H<inf>2</inf> Sensing at Room Temperature

The increasing demand of hydrogen (H2) as an alternative clean fuel emboldened the parallel development of extremely sensitive room-temperature H2 sensors for safety purposes. Molybdenum disulfide (MoS2) is an intriguing material, exhibiting a high chemical sensing ability. However, usage of MoS2 in H2 sensors has been limited and usually suffers from low sensitivity and selectivity, especially at room temperature. In this work, we report a highly sensitive and selective H2 sensor based on Pt nanoparticle-functionalized vertically aligned large-area MoS2 flakes. The fabricated Pt@MoS2 sensor exhibits a high sensitivity value of 23%, excellent reproducibility, fast response, and complete recovery at room temperature. The superior response of the sensor is attributed to the spillover effect and adsorption sites distributed on the Pt surface and the MoS2-Pt interface. The influence of operating temperature on the sensing performance is also investigated. Density functional theory calculations validate our experimental results and demonstrate higher adsorption of H2 for Pt@MoS2 leading to improved and selective H2 response. This study offers Pt nanoparticle-sensitized MoS2 as a potential candidate for the development of low-power and room-temperature H2 sensors for near future hydrogen vehicles and related technologies.