Carbon-doped boron-nitride fullerenes as efficient metal-free catalysts for oxidation of SO2: a DFT study

The aim of this study is to explore the potential of utilizing carbon-doped fullerene-like boron-nitride nanocages (B11N12C and B12N11C) as an efficient metal-free catalyst for the oxidation of SO2 to SO3 molecule in the presence of N2O. The oxidation of SO2 over B11N12C includes two steps. First, the N2O molecule is decomposed into an activated oxygen atom (O*) and N-2 molecule, and then the SO2 molecule is oxidized by the O* species. In the case of B12N11C and B12N12, however, the reaction starts with the coadsorption of SO2 and N2O molecules, followed by the decomposition of N2O and the formation of SO3 and N-2 species. According to our results, B11N12C exhibits larger catalytic activity for the SO2 oxidation compared with B12N11C and B12N12 clusters. The estimated activation energy for the SO2 + O* -> SO3 reaction catalyzed over the B11N12C surface is 5.8 kcal/mol, which is comparable with those reported about noble-metal catalysts. The results of this study can be useful for developing metal-free catalysts based on C-doped BN nanostructures.