Hydrothermal synthesis of spherical g-C3N4 and CdS composite photocatalyst with enhanced visible light photocatalytic activity

In this paper, spherical g-C 3 N 4 modified by N defect and O doping was prepared by a simple hydrothermal method , and combined with CdS to form a direct Z-type heterojunction . Combined with a series of characterizations (XRD, SEM, BET, FTIR and UV–vis DRS), the results show that the addition of CTAB brings a lot of positive charges on the surface of N-OCN. According to the principle of electrostatic attraction, positively charged N-OCN negatively charged CdS attract each other, which strengthens the close contact between CdS and N-OCN and plays an important role in stabilizing the formation of heterojunction. CdS is anchored to N-OCN through electrostatic interaction. Under the irradiation of visible light, the electrons on CB on positively charged N-OCN combine with holes on negatively charged CdS valence band, which improves the redox ability in photocatalytic reaction system. Taking methyl orange (MO) as a pollutant degradation model, the possible degradation mechanism was discussed in detail. This study provides a simple, effective and wide application method for the modification of g-C 3 N 4 .