First-principles investigations noble metals adsorbed MoS₂ for N₂O detection

Abstract By noble metal-doped MoS 2 , the gas adsorption effect and detection behaviors of N 2 O can be improved. In order to better find the gas adsorption substrate for N 2 O, we construct models of N 2 O adsorbed on intrinsic MoS 2 , defective MoS 2 , and MoS 2 doped with several noble metal atoms (Au, Ag, Cu, Pt, Pd). The energy band structure, electronic structure, differential charge density and optical properties of the systems are calculated. By comparing the adsorption energies of the intrinsic MoS 2 , defective MoS 2 and each adsorption system after doping, the results show that the adsorption energy of Cu-doped MoS 2 to N 2 O is the lowest case about −3.343 eV. The Cu-doped system has the most charge accumulation for adsorbing N 2 O, and the charge transfer amount is 1.68 | e| per molecule. Combined with the adsorption energy results, it can be explained that the adsorption effect of the Cu-doped system is the best. Compared with the intrinsic system, the band gap of the doped system is significantly reduced and a new impurity peak is formed near the Fermi level (E f ), which is beneficial to improve the conductivity of the system and improve the reducibility of the material surface. The density of states of the doped system increases and the probability of electron transition increases. The total density of state (TDOS) in the Cu-doped system is the most obvious, which indicates that the interaction between the N 2 O molecule and the Cu-doped MoS 2 system is more intense. According to the light absorption spectrum, when the metal-doped system reacts, the absorption spectrum undergoes a red shift and a new absorption peak appears in the infrared region, indicating that doping causes hybridization of orbitals and reduces the band gap, improving the conductivity of the adsorption system. According to the light reflection spectrum, when the doped system is adsorbed and reacts, the reflectivity in the visible light range is reduced, indicating that the utilization rate of visible light is increased and the response range of light is increased. Doping noble metals improves the conductivity and sensing performance of the MoS 2 system. Addressing the challenge of weak interactions between MoS 2 and N 2 O gas molecules, these findings can identify a more efficient MoS 2 -based gas sensor for N 2 O detection.