The effect of MoS2 modified with transition metal (Fe, Co, Ni, Cu) on H2O adsorption: A first principle study

MoS₂ has great potential as a humidity sensor, and doping is considered the most promising method to enhance the adsorption of H₂O molecule by MoS₂. Unfortunately, vacancy doping sacrifices the stability of the material while enhancing adsorption efficiency. Here, we use Fe, Co, Ni, Cu to modify the surface of MoS₂ and study the adsorption characteristics of H₂O molecule on MoS₂ before and after modification. The first principles calculations further indicate that partial transition metal (TM) doping can induce spin polarization in MoS₂. Spin polarization further enhances orbital hybridization between atoms, thereby improving adsorption performance. On the basis of qualitative analysis of thermodynamic stability and electrical properties, quantitative analysis was conducted on adsorption energy and charge transfer. The results indicate that the adsorption energy, in descending order, is Fe–MoS₂ > Co–MoS₂ > Ni–MoS₂ > Cu–MoS₂ > MoS₂. Compared with MoS₂, Fe–MoS₂ has the best adsorption effect among the four doping systems, with an adsorption energy increase of 22.1 times. Importantly, simulations of desorption time have demonstrated that Fe–MoS₂ and Co–MoS₂ exhibit a significant reduction in desorption time with increasing temperature and can be rapidly recycled.