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

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, and Ni) using first principles calculations. The 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 (-0.211e), 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 d_z² 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.