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

Abstract

For improving the photocatalytic activity, a new N-TiO 2−X /g-C 3 N 4 (NTCN) composite was designed and constructed successfully by a facile hydrothermal-calcination method. The co-doping N and Ti 3+ /Ov were achieved to reduce the band gap of TiO 2 , and g-C 3 N 4 nanosheets were coated firmly on the surface of N-TiO 2− X to form efficient heterojunctions. The photocatalytic activity of N-TiO 2−X /g-C 3 N 4 was evaluated fully under visible light irradiation to achieve the degradation of 2,4-dinitrophenylhydrazine (2,4-DNPH). When the content of g-C 3 N 4 in composite is 30 wt% (NTCN 0.3 ) with calcination temperature of 350 ℃, the photocatalytic 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 NTCN 0.3 composite. • A new N-TiO 2−X /g-C 3 N 4 composite was designed and successfully constructed. • the co-doping of N and Ti 3+ /Ov can effectively reduce the band gap of TiO 2 . • The degradation rate of 2,4-DNPH under visible light can reach 93.19%. • Apparent activation energy was obtained by degradation kinetics studies. • S-scheme charge transfer mechanism was proposed.