▎ 摘　　要

The adsorption of methane (CH4) gas is explored on the graphene nanoribbon (GNR) and doped GNR surface by first principle investigation. In present work, doping of GNR with Manganese (Mn) has shown very encouraging results. A comparative study of zigzag (ZGNR), armchair (AGNR) and defective (DGNR) graphene nanoribbon is carried out for sensing of CH4. The pristine ZGNR, AGNR and DGNR form show negligible adsorption of CH4. Whereas adsorption efficiency of all systems increases after doping these with Mn. The adsorption energy of ZGNR changed from-0.05 to-2.10 eV and of AGNR changed drastically from-0.13 to-2.94 eV hence changing electrical conductivity. There is nearly no change in energy value of DGNR. The density of state, band gap, binding distance and adsorption energy of GNR and GNR-Mn before and after CH4 adsorption are calculated. The results show that, AGNR-Mn can be an excellent material for CH4 gas sensing.