First-principles investigation on the sensitivity of germanene/graphene heterostructure toward methane gas

The adsorption behaviour of CH4 molecule on a perfect, vacancy-defected, and doped germanene/graphene heterostructure was investigated using density functional theory (DFT). The CH4 molecule was weakly adsorbed on the perfect substrate. The introduction of vacancies did not improve the activity of the germanene/graphene substrate, while doping atoms (B, N, S, V, Cr, and Ni) enhanced the adsorption stability of the CH4 molecule. The enhancement by transition metal dopants was more obvious than that of non-metal atoms. Among them, the V atom doped system has the strongest adsorption capacity for CH4 molecule. Compared with other studies, it was found that the adsorption capacity of V-VGe/G to CH4 molecule was better than most materials. Density functional theory is used to study the adsorption of CH4 molecule on perfect, vacancy-defected, and doping germanene/graphene heterostructures. The results show that the interaction between CH4 molecule and substrate is significantly enhanced by the introduction of atomic dopants, and the ability of transition metal atoms for enhancing the adsorption of the systems is stronger than that of non-metal atoms.