Boron-Decorated Graphitic Carbon Nitride (g-C3N4): An Efficient Sensor for H2S, SO2, and NH3 Capture

We investigated the interactions between nonboron (g-C 3 N 4 ) and boron-decorated (B-g-C 3 N 4 ) graphitic carbon nitride complexes with H 2 S, SO 2, and NH 3 molecules by first-principles calculations. Our results show a highly superior selectivity toward the H 2 S gas compared to the SO 2 molecule. In addition, by increasing the concentration of nitrogen defects at the edges of g-C 3 N 4 from 1.785 to 3.572%, we noticed a complete H 2 S dissociation, with the two hydrogen atoms chemisorbed on the g-C 3 N 4 planes while the sulfur atom (S) remained in the gaseous phase. However, the efficiency of the D site is altered by the gas–gas interaction where a partial dissociation of H 2 S occurs. Furthermore, our results show that doping g-C 3 N 4 with the B atom was very efficient to fix the S atom on the g-C 3 N 4 substrate. Moreover, decorating the g-C 3 N 4 edges with the B atom enhanced selectivity toward the H 2 S, SO 2, and NH 3 gases as they strongly chemisorbed on the B-g-C 3 N 4 complex. Furthermore, our results in the gas–gas interaction show the same trend as the earlier results reported for a single gas adsorption. These results predict that B-g-C 3 N 4 may be a better sensor for H 2 S, SO 2, and NH 3 compared to pure and nitrogen monovacancy defect g-C 3 N 4 .