Theoretical study on the adsorption and predictive catalysis of MnN4 embedded in carbon substrate for gas molecules

Abstract Toxic gases destroy the ecological environment and endanger human health, which enlightened the researchers in development of new materials and technologies that effectively collect and capture toxic gases, and convert to harmless gases with the aid of catalyst. Density functional theory (DFT) calculations are performed to evaluate the changes in adsorption energy, charge transfer, sensitivity and Gibbs free energy for MnN4-decorated graphene (MnN4-Gra), graphene nanoribbons (MnN4-GNR), graphene nanosheets (MnN4-GNS), carbon nanotubes (MnN4-CNT) and C60 fullerenes (MnN4-C60) after adsorbing gas molecules, including NO, NO2, CO, SO2, NH3, H2S, N2O, O2, H2O and CO2. The most stable adsorption configuration of the molecule on MnN4-CS can be determined by molecular electrostatic potential and adsorption energy. The adsorption properties of MnN4-CS are mainly affected by doped atoms, curvature and size of the substrate. Among five tested materials, MnN4-C60 has good adsorption energy for toxic gases and is suitable for collecting and trapping gases. MnN4-Gra, MnN4-GNR and MnN4-GNS are evaluated as catalysts for oxygen reduction reaction (ORR), MnN4-Gra, MnN4-GNR, MnN4-CNT are suitable as catalysts for CO oxidation. Also the normal operating temperatures of gas sensors were determined by Gibbs free energy and molecular dynamics (MD). This investigation provides valuable information for designing high-performance gas sensors.