Ab initio study of photocatalytic characteristics of graphitic carbon nitride assisted by oxalic acid

Using density functional theory, structural, electronic, and optical properties of GCN (graphitic carbon nitride) and OAGCN (graphitic carbon nitride combined with oxalic acid) were studied. By comparing HOMOs and LUMOs and excitonic binding energies, OAGCN has lower photoinduced electron–hole recombination rate than GCN. VBM and CBM levels of GCN and OAGCN were calculated, which shows that for GCN, only the electron at CBM contributes to produce radicals for removing pollutants, and for OAGCN, both the electron at CBM and the hole at VBM contribute to produce radicals for removing pollutants. In total, it can be said that OAGCN has higher photocatalytic activity than GCN.