Enhanced photocatalytic degradation of rhodamine B under visible light irradiation on mesoporous anatase TiO2 microspheres by codoping with W and N

• The preparation of metal–nonmetal codoped mesoporous anatase TiO2 microspheres.
• The high surface area of doped TiO2 mesoporous microspheres.
• The enhanced Vis-light activity of N-doped TiO2 by codoping with W.

Mesoporous anatase TiO2 microspheres were prepared via solvothermal method. Ammonium tungstate was used as the W source, and ammonia gas flowing in an ammonothermal reactor as the N source for codoping. TiO2:(W,N) mesoporous microspheres, which were prepared from solvothermal treatment at 160 °C for 16 h and thermal ammonolysis at 500 °C for 2 h after calcination, have high specific surface area of 106 m2 g−1. XPS results indicate the presence of NO, Ni and W6+ in the codoped mesoporous TiO2 microspheres. Monodoping with N shifts the absorption band edge of anatase TiO2 from ultraviolet region to visible region. Although codoping with W makes the visible light absorbance decrease a little, the photocatalytic degradation of a cationic dye rhodamine B (RhB) on mesoporous TiO2:(W,N) microspheres is increased to 1.7 times of that on mesoporous TiO2:N microspheres. This may due to decreasing recombination centers by W-doping charge compensation.

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