Enhancing AsH3 gas sensing properties via transition metal doping in divacancy graphene: a first-principles investigation

Abstract

Designing sensitive materials capable of efficiently adsorbing AsH3 is of great significance for industrial safety protection and toxic gas monitoring. In this work, we systematically investigate the adsorption behavior of AsH3 on pristine graphene and transition metal-doped divacancy graphene (TM-DVG, TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni) using first principles calculations. Results show that AsH3 interacts with pristine graphene primarily via weak physisorption. In contrast, TM-DVG exhibits significantly enhanced adsorption performance. The adsorption strength is governed by the degree of energy level matching and the competition between bonding and antibonding states in the electronic structure. Among numerous sensitive materials, Fe-DVG exhibits significant charge transfer (-0.211 e), moderate adsorption energy (-0.930 eV), and rapid recovery characteristics (420 s at 300 K), indicating its excellent sensing potential. Further analysis reveals that the strong interaction between the HOMO of AsH3 and the dz2 orbital of the Fe atom originates from appropriate energy level matching, symmetry matching, and maximal orbital overlap. Meanwhile, Fe-DVG exhibits good selectivity toward AsH3, making it an ideal candidate for AsH3 detection. This study provides a theoretical foundation for the design of graphene-based AsH3 sensors with high sensitivity and selectivity.