Adsorption behavior of H2S on P‒doped, V/P, Nb/P, and Ta/P‒codoped graphitic carbon nitride: A first-principles investigation

2020 
Abstract The adsorption behavior of H2S gas on the P‒doped, V/P, Nb/P, and Ta/P‒codoped g-C3N4 were theoretically investigated using density functional theory. The computed adsorption energy of H2S molecules over the P‒doped, V‒embedded, Nb‒embedded, Ta‒embedded, V/P‒codoped, Nb/P‒codoped, and Ta/P‒codoped g-C3N4 systems are −0.188, −3.141, −2.850, −3.388, −3.263, −2.970, and −3.523 eV, respectively. These results revealed that with embedding and codoping of g-C3N4, the interaction energy between H2S and V/P, Nb/P, Ta/P‒modified g-C3N4 systems significantly enhances. Furthermore, the band structure results exhibited that with adsorption of H2S on g-C3N4 and also embedded and codoped systems, the electrical conductivity of the g-C3N4 systems remarkably decreases owing to the induced new impurity energy states near the Fermi energy level. Also, the results of the relaxed structures displayed that with adsorption of H2S molecules on g-C3N4 and also the modified g-C3N4 with V, Nb, and Ta and also P elements, the initial planar structure of the pristine g-C3N4 automatically become buckle because the stability of wrinkles structure of g-C3N4 is more than that of the flat structure. Additionally, the results of the Lowdin charge analysis revealed that electron transfer occurs from orbitals of transition metals to the orbitals of H2S molecules for all of the g-C3N4 systems. Finally, current research introduces Ta/P‒codoped g-C3N4 system with adsorption energy of −3.523 eV as the highest sensitive, and low-cost gas sensor candidate for sensing and removing H2S gas from the atmosphere.
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