First-principles prediction of enhanced hydrogen sensing performance of Pt–MoS2 monolayer upon pre-adsorption of oxygen gas

Developing hydrogen sensors with high sensitivity and selectivity is particularly critical for applications of hydrogen energy. In this work, the sensing mechanisms of Pt-doped and O2-pre-adsorbed MoS2 monolayer toward hydrogen gas are investigated by first-principles. The results of adsorption energies, adsorption distance, band gaps change and Mulliken charge suggest that the doping of Pt in MoS2 leads to more stable configuration and better sensitivity for hydrogen adsorption, and this performance is further improved with pre-adsorption of oxygen molecule on MoS2. The strong hybridization indicates the strong interaction and chemisorption between the constructed oxygen and Pt–MoS2. The sensing mechanism of Pt–MoS2 is also revealed by the energy profile for dissociation of O2 and H2 molecules on Pt–MoS2, the reaction process increases the charge carrier concentration and conductivity of the sensing material. The proposed numerical framework provides a perspective foundation for developing high-performance and complicate gas sensor.