A Theoretical Study of Single-Atom Catalysis of CO Oxidation Using Au Embedded 2D h-BN Monolayer: A CO-Promoted O2 Activation

The CO oxidation behaviors on single Au atom embedded in two-dimensional h-BN monolayer are investigated on the basis of first-principles calculations, quantum Born-Oppenheim molecular dynamic simulations (BOMD) and micro-kinetic analysis. We show that CO oxidation on h-BN monolayer support single gold atom prefers an unreported tri-molecular Eley-Rideal (E-R) reaction, where O-2 molecule is activated by two pre-adsorbed CO molecules. The formed OCOAuOCO intermediate dissociates into two CO2 molecules synchronously, which is the rate-limiting step with an energy barrier of 0.47 eV. By using the micro-kinetic analysis, the CO oxidation following the tri-molecular E-R reaction pathway entails much higher reaction rate (1.43 x 10(5) s(-1)) than that of bimolecular Langmuir-Hinshelwood (L-H) pathway (4.29 s(-1)). Further, thequantum BOMD simulation at the temperature of 300 K demonstrates the complete reaction process in real time.