Highly enhanced H2S gas sensing and magnetic performances of metal doped hexagonal ZnO monolayer

Understanding the interaction mechanisms of hydrogen sulfite (H2S) with hexagonal ZnO monolayer (h-ZnO) is important in exploiting h-ZnO-based sensing devices. In this study, the effects of transitional metals on interaction of H2S with various h-ZnO have been investigated by density functional theory calculations. It was found that the electronic properties of h-ZnO/H2S systems can be effectively tuned by manipulating the configurations of H2S molecule on plane surface of the h-ZnO. Transitional metals (Pd, Au, Fe, and Co) doped h-ZnO exhibit much higher adsorption capacity to H2S compared with their undoped counterparts. The electronic and magnetic behaviors of the h-ZnO can be effectively modulated by the metal dopants and H2S adsorption. H2S adsorption does not change the magnetic properties of the nonmagnetic (NM) semiconductors, like Pd-h-ZnO and Au-h-ZnO, as well as the ferromagnetic half metal (FM-HM) of Co-h-ZnO. In contrast, the ferromagnetic metal (FM-metal) Fe-h-ZnO is converted to FM-HM after H2S adsorption. The results of this research indicate that transition metal doped h-ZnO nanosheets could be utilized as building blocks to design H2S sensors and magnetic devices.