Temperature-Based Selective Detection of Hydrogen Sulfide and Ethanol with MoS2/WO3 Composite.

A sensitive and temperature-based selective sensor toward hydrogen sulfide and ethanol using MoS2/WO3 composite as a sensing surface was developed in this work. The MoS2/WO3 nanocomposite was successfully obtained using a facile two-step method. Structural analysis revealed the successful formation of the composite. Further, the n-type semiconducting nature as revealed in the initial gas-sensing measurements was also confirmed via Mott-Schottky plots. The composite-based sensor showed preferential detection of ethanol (260 °C) and hydrogen sulfide (320 °C) by simply modulating the temperature of the sensor device. The device also displayed repeatability and long-term stability at respective operating temperatures. Improved sensitivity and selectivity are ascribed to synergistic effects arising from the formation of n-n type heterostructures. The present work indicates the potential use of composite-based heterojunctions to tune the sensing parameters and provide new possibilities to enhance the applications of MoS2 and metal-oxide semiconductor-based composites.