Publication

Abstract : Hydrogen is a energy carrier for fuel cells, chemical processing, petroleum refining, and energy storage; however, its flammability necessitates reliable detection systems. (2D) MoS 2 nanosheets were synthesized via a two-step method comprising hydrothermal synthesis followed by liquid-phase sonication exfoliation. Material characterization confirmed crystalline 2H- MoS 2 nanosheets with a layered, porous, interconnected morphology. MoS 2 nanosheets served as the sensing layer in a chemiresistive hydrogen sensor. The sensing mechanism is attributed to an oxygen-assisted surface charge-transfer process in which hydrogen reacts with chemisorbed oxygen species and returns electrons to the MoS 2 conduction channel. Charge transport modulation across interconnected nanosheet junctions contributes to the sensing response. At the optimal operating temperature of 200 °C, the sensor exhibited a maximum response of 63% to 100 ppm H 2 , with response and recovery times of 50 s and 35 s, respectively. The sensing performance is ascribed to synergetic effects of sulfur-vacancy-created active sites, efficient surface charge transfer, and inter-sheet barrier modulation. These findings demonstrate the potential of defect-engineered MoS 2 nanosheets for hydrogen sensing.