DFT Study of Zn-Modified SnP 3 : A H 2 S Gas Sensor with Superior Sensitivity, Selectivity, and Fast Recovery Time.

The adsorption properties of Cu, Ag, Zn, and Cd-modified SnP 3 monolayers for H 2 S have been studied using density functional theory (DFT). Based on phonon spectrum calculations, a structurally stable intrinsic SnP 3 monolayer was obtained, based on which four metal-modified SnP 3 monolayers were constructed, and the band gaps of the modified SnP 3 monolayers were significantly reduced. The adsorption capacity of Cu, Zn-modified SnP 3 was better than that of Ag, Cd-modified SnP 3 . The adsorption energies of Cu-modified SnP 3 and Zn-modified SnP 3 for H 2 S were -0.749 eV and -0.639 eV, respectively. In addition, Cu-modified SnP 3 exhibited chemisorption for H 2 S, while Zn-modified SnP 3 exhibited strong physisorption, indicating that it can be used as a sensor substrate. Co-adsorption studies showed that ambient gases such as N 2 , O 2 , and H 2 O had little effect on H 2 S. The band gap change rate of Zn-modified SnP 3 after adsorption of H 2 S was as high as -28.52%. Recovery time studies based on Zn-modified SnP 3 showed that the desorption time of H 2 S was 0.064 s at 298 K. Therefore, Zn-modified SnP 3 can be used as a promising sensor substrate for H 2 S due to its good selectivity, sensitivity, and fast recovery time.