Preparation of g-C3N5/g-C3N4 heterojunction for methyl orange photocatalytic degradation: Mechanism analysis

1D/2D g-C3N5/g-C3N4 heterojunction (1D/2D-N5/N4) is prepared by direct thermal polymerization for methyl orange (MO) removal from wastewater. The characterization analysis indicates that 1D/2D-N5/N4 has onedimensional g-C3N5 nanorods and two-dimensional g-C3N4 nanosheets. The heterojunction between g-C3N5 and g-C3N4 is formed, which contributes to MO removal. The MO photocatalytic degradation removal of the 1D/ 2D-N5/N4 is 99.6 %. Photocatalytic degradation mechanism analysis indicates that the formed heterojunction between g-C3N5 and g-C3N4 improves the absorption intensity and inhibits the recombination of photoelectrons and holes. Besides, the superposition of similar & pi;-& pi;* conjugated systems between g-C3N5 and g-C3N4 also improves the photocatalytic activity of 1D/2D-N5/N4. The O2  and h+ play an important role in the MO photocatalytic degradation process. The MO photocatalytic degradation removal of 1D/2D-N5/N4 still has 92.20 % after five cycles. Possible MO degradation pathway is analyzed using the UPLC-MS. The present work demonstrates that 1D/2D-N5/N4 is an efficient photocatalyst for MO removal.