Ultrasensitive and selective room temperature H2S detection using Pd-doped MoS2 synthesized via APCVD

Abstract

The detection of trace amounts of hazardous hydrogen sulfide (H<inf>2</inf>S) gas is crucial for environmental monitoring and industrial safety. In this study, pristine and palladium (Pd)-doped molybdenum disulfide (MoS<inf>2</inf>) thin films with varying Pd concentrations (1, 2, 5, and 10 at%) were synthesized on SiO<inf>2</inf>/Si substrates using atmospheric pressure chemical vapor deposition (APCVD). Gas sensing performance was analyzed at room temperature (RT) in a dynamic flow gas sensing setup. The 5 at% Pd-doped MoS<inf>2</inf> sensor exhibited the best response of 276 % at 100 ppm H<inf>2</inf>S, significantly outperforming pristine MoS<inf>2</inf>, which showed a response of 96 %. The sensor also exhibited rapid response and recovery times of 45 and 65.8 s, respectively. A limit of detection (LoD) of 0.3 ppb and a limit of quantification (LoQ) of 0.99 ppb were achieved, indicating ultrasensitive detection capabilities. Additionally, density functional theory (DFT) studies were conducted to provide theoretical validation of the experimental results, to confirm that the Pd doping changes the electronic properties of MoS<inf>2</inf> and enhances its interaction with H<inf>2</inf>S gas molecules. Comprehensive characterization techniques, including X-ray diffraction (XRD), Raman spectroscopy, I-V characteristics, and X-ray photoelectron spectroscopy (XPS) confirmed the successful synthesis and doping of MoS<inf>2</inf> with Pd. This combined experimental and computational study provides valuable insights into the effects of Pd doping on MoS<inf>2</inf> resulting in the superior gas sensing performance of the 5 at% Pd-doped MoS<inf>2</inf> through the present investigations. As grown 5 at% Pd-doped MoS<inf>2</inf> sensor was characterized by excellent reproducibility, long-term stability and selectivity, making it a promising candidate for real- time, highly sensitive H<inf>2</inf>S detection at trace levels © 2025 Elsevier B.V., All rights reserved.