The catalytic oxidation of carbon monoxide (CO) on B-doped C3N nanosheet is investigated by first-principle density functional theory calculations. According to our results, the incorporation of a B atom can induce a noticeable charge redistribution into C3N monolayer, which results in the enhancement of O2 adsorption. The activation energy for the rate-determining step of CO + O2 reaction via the Langmuir–Hinshelwood (LH) mechanism is calculated to be 0.32 eV, which is 0.24 eV smaller than that of the Eley–Rideal (ER) mechanism. This can be mainly related to the more favorable CO-5σ → O2-2π* orbital interaction in the former mechanism, which facilitates the formation of OCOO intermediate over B-doped C3N. The results of this study provide a theoretical evidence for the potential of B-doped C3N as a novel and metal-free catalyst in the CO oxidation reaction.
