A first-principles investigation of PH3 gas adsorption on the graphitic carbon nitride sheets modified with V/P, Nb/P, and Ta/P elements

Abstract The adsorption characteristics of phosphine (PH3) gas on the Nb‒, V‒, Ta‒embedded, P‒doped, and also Nb/P‒, Ta/P‒, and V/P‒modified graphitic carbon nitride (gCN) materials were theoretically studied. The results demonstrated that the adsorption of PH3 on these systems causes changes in the structures, band gap energy, magnetic moments, and charge transfer in the gCN materials. The results of adsorption energy demonstrated that the abilities of gCN systems in the adsorption of PH3 are in the order of Ta/P‒codoped (-2.731 eV) > Nb/P‒codoped (-1.581 eV) > V/P‒codoped (-1.389 eV) > Ta‒embedded (-2.595 eV) > Nb‒embedded (-1.559 eV) > V‒embedded (-1.383 eV) > P‒doped gCN (-0.272 eV). These results illustrated that the Ta/P–modified gCN system is more appropriate for the detection and removal of PH3 molecules than the other modified gCN materials. It was found that the optimized primary structure of the gCN materials automatically converts from flat to buckle structure after the interaction with PH3 gas. Additionally, the band structure results indicated that with the adsorption of PH3 gas on the gCN systems, and also modification of gCN with V/P, Ta/P, and Nb/P elements, the conductivity of gCN considerably increased due to the created new impurity energy levels close to Fermi level. Furthermore, the results of electron transfer analysis and partial density of states revealed that the interaction energy between PH3 gas and Ta/P‒modified system is stronger than those of the other g-CN materials. Consequently, it can be deduced that the Ta/P–modified gCN is a good candidate for sensing and removing PH3 from the surroundings.