Computational studies of chalcogen doped on graphene vs. chalcogen doped on CNT and their role in the catalytic performance of electrochemical CO2 reduction

The extensive use of fossil fuels has increased atmospheric carbon dioxide (CO2) since the beginning of the industrial revolution. Electrochemical CO2 reduction holds tremendous potential for CO2 conversion and utilization due to its ability to convert CO2 into valuable chemicals and fuels. The primary objective of carbon dioxide conversion is using carbon dioxide to produce hydrocarbon molecules, which can then be used to make "green fuels". Using the theoretical approach of dispersion correction of density functional theory (DFT-D3), we robustly investigate chalcogen (Se, Te)-doped graphene and carbon nanotube (CNT) as catalysts for the electrochemical reduction of CO2 in the gas phase. Doped structures can convert CO2 to CH3OH due to their efficient catalytic properties. All catalytic properties of doped structures are evaluated by calculating their electrostatic potential (ESP), electron localization function (ELF), and density of states (DOS). The results show that Se-doped graphene is the most reactive material for gas adsorption. The Gibbs free energies for the CO2 hydrogenation to CH3OH are in the following order: Te-doped CNT < Se-doped CNT < Te-doped graphene < Se-doped graphene. The absorption spectrum of the chalcogen (Se, Te)-doped graphene and carbon nanotube (CNT) compounds have been obtained via the Ultraviolet-Visible optical spectra analysis. According to the turnover frequency analysis (TOF), the electrochemical CO2 reduction catalytic cycle in the presence of Se-doped graphene occurs faster than in Se-doped graphene occurs faster than in other structures. Compared to the other structures, the Se-doped graphene has the most significant impact on the electrochemical CO2 reduction catalytic activity. This is a general characteristic of the mechanism for CO2 conversion catalyzed by Se-doped graphene (spontaneous thermodynamics). Our findings would illuminate the experimental studies and guide future experiments.