Construction of a novel N-doped oxygen vacancy-rich TiO2 N-TiO2-X/g-C3N4 S-scheme heterostructure for visible light driven photocatalytic degradation of 2,4-dinitrophenylhydrazine

For improving the photocatalytic activity, a new N-TiO2-X/g-C3N4 (NTCN) composite was designed and constructed successfully by a facile hydrothermal-calcination method. The co-doping N and Ti3+/Ov were achieved to reduce the band gap of TiO2, and g-C3N4 nanosheets were coated firmly on the surface of NTiO2-X to form efficient heterojunctions. The photocatalytic activity of N-TiO2-X/g-C3N4 was evaluated fully under visible light irradiation to achieve the degradation of 2,4-dinitrophenylhydrazine (2,4-DNPH). When the content of g-C3N4 in composite is 30 wt% (NTCN0.3) with calcination temperature of 350 degrees C, the pho-tocatalytic degradation rate of 2,4-DNPH can reach 93.19% after 70 min irradiation, which is much higher than those of monomers and other composites. Furthermore, the degradation process was verified to be pseudo-first-order kinetic model, and the apparent activation energy is 17.23 +/- 2.47 kJ mol(-1). S-scheme heterojunction mechanism was speculated to explain the extremely high photocatalytic degradation ability of NTCN0.3 composite. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A new N-TiO2-X/g-C3N4 (NTCN) composite with improved photocatalytic activity was successfully designed and constructed by co-doping N and Ti3+/Ov to reduce the band gap of TiO2. The composite showed significantly higher photocatalytic degradation rate of 2,4-dinitrophenylhydrazine (2,4-DNPH) under visible light irradiation compared to monomers and other composites.