Oxygen-rich vacancy TiO2 for efficient photocatalytic H2O2 production
Nano TiO2 photocatalyst(TiO2-OV)rich in oxygen vacancy(OV)was prepared from solid-state chemical reduction of nano TiO2(P25),and characterized by XRD,SEM,XPS,EPR and UV-Vis DRS spectra.The photocatalytic performance of TiO2-OV prepared with different amounts of NaBH4(P25 2.0 g)for H2O2 production was evaluated via photocatalysis experiment and photoelectric chemical measurement,with the photocatalytic reaction mechanism further speculated.The results showed that,a highly crystalline mixture of anatase and rutile phase,TiO2-OV prepared with 10 mg NaBH4 exhibited the best photocatalytic H2O2 production performance,with the direct band gap energy(Eg)and conduction band(CB)energy of 2.77 and-0.84 eV.The production efficiency of H2O2 reached 1752.80 μmol/(g·h)under simulated sunlight irradiation,which was attributed to the fact that OV was generated on the surface of TiO2,and OV with appropriate concentration could be used as an electron trap,thus improving the separation efficiency of photogenerated electron-hole.After 4 times of recycling,TiO2-OV displayed slight reduction in the catalytic performance.The active species of H2O2 photocatalyzed by TiO2-OV were superoxide radical,hydroxyl radical and hole.In addition,CH3OH played an important role in promoting photocarrier separation and generating H2O2.
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