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

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 (MoSe2-WSe2) nanomaterials using a liquid phase exfoliation technique and its H2 sensing performance. The material characterizations confirmed the successful exfoliation into a hexagonal sheet-like, nanocrystalline MoSe2-WSe2 nanostructure. The study further assessed the sensor's response to H2 gas, for concentrations of 5-25 ppm at room temperature, comparing the performance of MoSe2-WSe2 sensor with a pristine WSe2 sensor. The MoSe2-WSe2 sensor outperformed the pristine WSe2 sensor with a response of 59.57%, rapid response times and recovery times (16 sand 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 H2 (at relative-humidity from 40% to 90%). The hydrophobic nature of MoSe2-WSe2 (CA = 141.4 degrees) aligns with the first principle studies, showing almost no change in bandgap when exposed to humidity. These findings emphasize the potential of MoSe2-WSe2 heterostructure sensors for detecting H2 in humid conditions, filling a gap in research and advancing gas sensing technology for environmental safety.