Preparation Of Doped Black Titanium Dioxide And Its Photocatalytic Activity

Titanium dioxide（TiO₂）, as the most widely used oxide semiconductor, has attracted considerable interest owing to its various applications in solar-driven hydrogen production, photocatalytic decomposition of pollutants, solar cells and so forth,although the wide-band-gap material（3.2 e V） captures about 5% of solar energy.Many investigations have been attempted to enhance visible-light absorption by band structure engineering（e.g. element doping and oxygen deciency）. Nevertheless, the visible-light power harvest remains insufficient due to little effective light absorption and many carrier-recombination centers. Very recently, the hydrogenation of black titania can boost its visible and infrared light absorption and ultraviolet（UV） light photocatalytic activity,In the reports, black TiO₂ shows a great photocatalytic performance. This paper adopted the sol-gel synchronous synthesis method combined with an in-situ solid-state chemical reduction approach, followed by the mild calcinations（350℃） in argon atmosphere. To prepared the black N-TiO₂; Ni-TiO₂; N-Ni-TiO₂ and TiO₂ photocatalyst, studied photocatalytic mechanism and doping mechanism of doped modification TiO₂ catalyst degradating methyl orange and Rhodamine B in visible light.The prepared samples were characterized by X-ray photoelectron spectroscopy（XPS）, Fourier transformation infrared spectroscopy（FT-IR）, transmission electron microscopy（TEM）, X-ray diffraction（XRD）, specific surfacte area analyses（BET）, Raman, UV-visible diffuse reflectance spectroscopy（UV-vis DRS） and EPR.It was showed that the doping amount of urea element and calcining temperature have influence on the performance of catalyst.The experimental results proved that the band gap of black N-TiO₂ about 2.05 e V which have an excellent visible light absorption performance. When nitrogen doping amount reached 0.1 mol and calcination temperature was 450℃, the prepared catalyst have the best photocatalytic degradation efficiency under visible light irradiation 150 minutes. The initial MO and Rh B removal of black N-TiO₂ was 93.27% and 93.64%, respectively.It was showed that the doping amount of Ni element and calcination temperature have influence on the performance of catalyst. The modified TiO₂ with 2 mol% Ni content and calcination temperature was 450℃, The experimental results prove that the band gap of black Ni-TiO₂ was about 1.96 e V which have an excellent visible light absorption performance. The prepared catalyst have the best photocatalytic degradation efficiency under visible light irradiation 150 minutes. The initial MO and Rh B removal of black Ni-TiO₂ was 95.38% and 95.86%, respectivelyBlack N-Ni-TiO₂ is about 1.82 e V which have an excellent visible light absorption performance. The experimental results confirmed that when the modified TiO₂ with 2 mol% Ni content and nitrogen doping amount reach 0.1 mol, calcination temperature is 450℃, the prepared catalyst have the best photocatalytic degradation efficiency under visible light irradiation 150 minutes, the initial MO and Rh B removal of black Ni-TiO₂ was 98.18% and 98.26%, respectively.