Co Implanted Ψ-graphene: A Non-Noble Metal Single-Atom Catalyst for Proficient CO Oxidation Reaction

Single-Atom Catalysts (SACs) have procured heightened attention of the research community across the globe due to their astounding catalytic behaviour towards some prime chemical reactions. Herein, the catalytic performance of non-noble metal, cobalt single-atom supported over Ψ-graphene (Co@PG) addressed towards CO oxidation reaction by means of first-principles-based, dispersion corrected density functional theory (DFT) calculations. The higher diffusion barrier of Co over Ψ-graphene evidently authenticate the stronger interaction of Co with Ψ-graphene and robust stability of overall system, hence prelude the cluster formation possibility. Further, the temperate interaction of reactants (CO, O2) affirms that the Co@PG is brilliantly effective in hosting and activating reactants, an indispensable condition to commence any catalytic reaction cycle. The analysis of electronic reactivity descriptors (ERDs) like d-band centre (ϵd) and fractional filling of d-band (fl), by employing improved d-band model, emphasize that the minority-spin states of Co atom would engage predominantly in the interaction with the reactants. Latterly, CO oxidation reaction over Co@PG was carried out with two different mechanisms, viz., Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) pathways for detailed analysis. Computation of minimum energy path (MEP) and activation barriers reveal that the Co@PG favours the ER mechanism, with reaction barrier of 0.19 eV and 0.27 eV for first and second half reactions respectively, both of them being highly exothermic validating the viability of the overall process. Accordingly, present investigation insinuates that Co@PG can be a potent, non-noble metal, practically operational catalyst for CO oxidation reaction.