Graphite phase carbon nitride may h

Graphite phase carbon nitride may have two stable structures, with triazine ring (C3N3) and heptaazine ring (C6N7) as the basic structural units extending infinitely to form a network structure g1-C3N4 and g2-C3N4, between layers Relying on weak Van der Waals bonding, the layer spacing is 0.326 nm. In both structures, the C and N atoms are sp2 hybridized to form a highly delocalized r conjugated system through lone pairs of electrons in the pz orbital. Kroke et al. Calculated that g2-C3N4 is more stable than the former. However, in the actual reaction, the structure of g-C3N4 will be affected by many factors such as the preparation method and the reaction precursor. Unlike graphene's zero-energy band gap, g-C3 N4 bulk materials, multiple layers and single layers all have band gaps, and are a new type of non-metal organic semiconductor. There is a forbidden band width of 2.7 eV between the energy bands of the bulk g-C3N4, so g-C3N4 can absorb blue-violet light with a wavelength of less than 475 nm in the solar spectrum. Compared with the traditional photocatalyst Ti02, which can only produce photocatalytic reaction under the drive of ultraviolet light, g-C3N4 broadens the utilization of solar spectrum and effectively realizes the response and absorption of visible light. In addition, a stable interface can be formed by compounding with a metal element, thereby improving the separation efficiency of photocarriers and effectively improving the utilization rate of visible light.