Humidity tolerant enhanced hydrogen gas sensing using MoSe2-WSe2 heterostructures: An experimental and computational insights

Abstract

In recent times, air pollution’s threat to humanity highlights the urgent need for advanced sensors to monitor harmful gases, essential for industrial regulation, gas leak detection, and air quality surveillance. Two-dimensional transition metal dichalcogenides (TMDCs) has garnered noteworthy attention as potential materials for gas sensing. This paper investigates the synthesis and characterization of a heterostructure composed of molybdenum diselenide with tungsten diselenide (MoSe${}_2$-WSe${}_2$) nanomaterials using a liquid phase exfoliation technique and its H${}_2$ sensing performance. The material characterizations confirmed the successful exfoliation into a hexagonal sheet-like, nanocrystalline MoSe${}_2$-WSe${}_2$ nanostructure. The study further assessed the sensor’s response to H${}_2$ gas, for concentrations of 5–25 ppm at room temperature, comparing the performance of MoSe${}_2$-WSe${}_2$ sensor with a pristine WSe${}_2$ sensor. The MoSe${}_2$-WSe${}_2$ sensor outperformed the pristine WSe${}_2$ sensor with a response of 59.57%, rapid response times and recovery times (16 s and 30 s respectively), low detection limit of 5.55 ppm, good repeatability, and high durability (30 days). Additionally, the impact of humidity was evaluated at 25 ppm H${}_2$ (at relative-humidity from 40% to 90%). The hydrophobic nature of MoSe${}_2$-WSe${}_2$ (CA = 141.4°) aligns with the first principle studies, showing almost no change in bandgap when exposed to humidity. These findings emphasize the potential of MoSe${}_2$-WSe${}_2$ heterostructure sensors for detecting H${}_2$ in humid conditions, filling a gap in research and advancing gas sensing technology for environmental safety.