Non-metal atom anchored BC3 sheet: a promising low-cost and high-activity catalyst for CO oxidation

Abstract

Graphene-like BC₃ monolayer as a new semiconducting nanomaterial has many unique properties. First, we investigate the adsorption behaviors of different adatoms (N, Si and P) on pristine and single-vacancy of BC₃ (pri- and SV-BC₃) using first-principles calculations. It was found that the non-metal (NM) adatoms have small diffusion barriers and tend to be mobile on the pri-BC₃ sheet; yet, these NM atom-doped BC₃ systems (NM-BC₃) exhibited high stability. Second, the adsorption of O₂ molecule on the Si-BC₃ system was more stable than that on other substrates (N- and P-BC₃), resulting in a change in the electronic structure and magnetic properties of the system. Moreover, the possible CO oxidation reactions on the Si-BC₃ sheet through the Eley–Rideal (ER) mechanism were comparatively investigated. For the initial step, the preadsorbed O₂ reacting with CO to form CO₃ or OOCO complex had a smaller energy barrier (<0.50 eV) than the dissociation reaction of the O₂ molecule. The formation of the CO₃ complex was quite stable on the Si-BC₃ sheet; yet, the presence of the CO molecule promoted the decomposition of the CO₃ complex and then formed two CO₂ molecules through ER reactions. These results contribute toward designing more effective and metal-free single-atom catalysts and broaden the applications of graphene-like materials.