Preparation of the Graphite Phase Carbonic Nitrogen(g-C3N4) for Photocatalytically Reducing CO2

The graphite phase carbon nitride (g-C₃N₄) semiconductors with different morphologies and photocatalytic performance were prepared by polycondensation method, using urea and melamine as precursors respectively. The catalytic performance of the g-C₃N₄ was measured by the reduction of CO₂ in methanol under light irradiation. X-ray diffraction (XRD)、Scanning electron microscope (SEM)、Transmission electron microscope (TEM)、Uv-vis spectrophotometry (Uv-vis)、Fourier transform infrared spectroscopy (FTIR)、Specific surface area measurements (BET) and Fluorescence spectrum (PL )were applied to analyze the influence of different precursors to the photocatalytic activity of g-C₃N₄. Results showed that g-C₃N₄ using urea as precursor had better photocatalytic activity for CO₂ reduction and the formation rate of methyl formate (MF) in methanol reached up to 512.8µmol/gcat·h, nevertheless that of the g-C₃N₄ made from melamine was only 257.3 µmol/gcat·h.