论文部分内容阅读
Effects of La, N, and P doping on the structural, electronic and optical properties of TiO_2 synthesized from TiCl_4 hydrolysis via a microwave-hydrothermal process were investigated by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy, electron paramagnetic resonance, UV-vis absorbance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy. The results showed that the presence of La in the tri-doped TiO_2 played a predominant role in inhibiting the recombination of the photogenerated electrons and holes. The existence of the substitutional N, interstitial N, and oxygen vacancies in TiO_2 lattices led to the band gap narrowing. It was P-doping rather than La or N doping that played a key role in inhibiting both anatase-to-rutile phase transformation and crystal growth, in stabilizing the mesoporous textural properties, and in increasing the content of surface bridging hydroxyl. Moreover, the tri-doping significantly enhanced the surface Ti~(4+)-O~(2-)-Ti~(4+)-O~(-·) species. All above-mentioned factors cooperated to result in the enhanced photoactivity of the tri-doped TiO_2. As a result, it exhibited the highest photoactivity towards the degradation of 4-chlorophenol(4-CP) under visible-light irradiation among all samples, which was much superior to commercial P25 TiO_2.
Effects of La, N, and P doping on the structural, electronic and optical properties of TiO 2 synthesized from TiCl_4 hydrolysis via a microwave-hydrothermal process were investigated by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy, electron paramagnetic resonance, UV-vis absorbance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy. The results showed that the presence of La in the tri-doped TiO 2 played a predominant role in inhibiting the recombination of the photogenerated electrons and holes. The existence of the substitutional N, interstitial N, and oxygen vacancies in TiO 2 lattices led to the band gap narrowing. It was P-doping rather than La or N doping that played a key role in inhibiting both anatase-to-rutile phase transformation and crystal growth, in stabilizing the mesoporous textural properties, and in increasing the content of surface bridging hydroxyl , the tri-doping significantly enhanced the surface Ti ~ (4 +) - O ~ (2 -) - Ti ~ (4 +) - O ~ of the tri-doped TiO_2. As a result, it exhibited the highest photoactivity towards the degradation of 4-chlorophenol (4-CP) under visible-light irradiation among all samples, which was much superior to commercial P25 TiO_2.