Adsorption of C2H2 on heteroatom-decorated graphene

Abstract

There remains considerable debate over the adsorption mechanism of acetylene in transformer fault gas detection. Herein, a graphene-based gas sensor with distinct decorated N, B configuration was constructed and evaluated via DFT. The adsorption and activation of C₂H₂ can be better facilitated over B-decorated pyridinic N sites than that on graphitic N and pyrrolic N configurations, presenting the adsorption energies of −0.22, −0.17 and 0.16 eV, respectively. Electron localization function (ELF) configurations and Bader charge analysis indicate that the electronic interaction between the graphitic substrates and C₂H₂ maybe responsible for tuning C₂H₂ adsorption behavior since the electron acceptor C₂H₂ transfers 0.497, 0.459 and 0.206 e from B-decorated pyridinic N, graphitic N and pyrrolic N configurations, respectively. Compared with pyridinic-N/G, the modification by B destroys the π electron pair of graphene, which is not conducive to the activation of the graphene surface. Additionally, in the DOS analysis, there is a clear overlap between B and N atoms, confirming the favorable contribution of B atoms to the adsorption performance. Compared with the other two co-doping structures, the pyridinic N–B/G structure has a higher p-band center, ensuring superior adsorption and activation capabilities for C₂H₂ during the reaction process. Significant contributions have been made by this research to the application of non-metal-doped graphene materials in gas sensor devices and the synthesis of highly efficient catalysts.