室内装饰品负载氮掺杂氧化钛的光催化性能

采用钛醇盐水解法与溶胶凝胶法,以氨水、尿素、三乙胺为氮源,制备了纳米TiO2-xNx光催化剂。为了在净化室内空气的同时能够装饰环境,提出了喷涂和浸泡2种工艺将光催化剂负载于室内装饰品,并在模拟太阳光的照射下对室内污染物甲醛进行降解。XRD、UV-Vis光谱及XPS分析结果表明,在烧结温度为400℃时得到的3种TiO2-xNx是锐钛矿相,其中以尿素为氮源的TiO2-xNx温度达到600℃时开始发生相转变,3种TiO2-xNx在可见光区域的400～550 nm均出现新的吸收;以氨水、尿素和三乙胺为氮源制备的TiO2-xNx的掺氮量分别为2.77%、0.29%和0.47%。以氨水为氮源制备的光催化剂,14 h降解甲醛的效率达到了95%;以三乙胺为氮源制备的光催化剂7 h降解甲醛的效率达到了96%。因此,应用喷涂法在室内装饰品上负载光催化剂降解室内污染物具有很好的应用前景。

Synthesis and Characterization of Novel N-doped TiO2 Photocatalyst with Visible Light Active

A novel N-doped TiO2 （N1-N2-TiO2） with substitutional and interstitial N impurities simultaneously was successfully synthesized. The catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, photoluminescence, and electron paramagnetic resonance. The results demonstrated that the nitrogen was substituted for the lattice oxygen atoms, and was also interstitially doped into the TiO2 lattice. The photocatalytic tests indicated that the N1-N2-TiO2 showed the highest photocatalytic activities of all the N-doped TiO2 under visible light, attributing to the synergetic effect of substitutional and interstitial nitrogen of N-doped TiO2.

Nitrogen-doped TiO_2 microsheets with enhanced visible light photocatalytic activity for CO_2 reduction

Nitrogen-doped anatase TiO 2 microsheets with 65%（001） and 35%（101） exposed faces were fabricated by the hydrothermal method using TiN as precursor in the presence of HF and HCl. The samples were characterized by scanning electron microscopy,X-ray diffraction,N2 adsorption,X-ray photoelectron spectroscopy,UV-visible spectroscopy,and electrochemical impedance spectroscopy. Their photocatalytic activity was evaluated using the photocatalytic reduction of CO2. The N-doped TiO 2 sample exhibited a much higher visible light photocatalytic activity for CO2 reduction than its precursor TiN and commercial TiO 2（P25）. This was due to the synergistic effect of the formation of surface heterojunctions on the TiO 2 microsheet surface,enhanced visible light absorption by nitrogen-doping,and surface fluorination.

Preparation of Nitrogen-doped TiO2 Nanoparticle Catalyst and Its Catalytic Activity under Visible Light

N-doped TiO2 nanoparticle photocatalysts were prepared through a sol-gel procedure using NH4C1 as the nitrogen source and followed by calcination at certain temperature. Systematic studies for the preparation parameters and their impact on the structure and photocatalytic activity under ultraviolet （UV） and visible light irra-diation were carried out. Multiple techniques （XRD, TEM, DRIF, DSC, and XPS） were commanded to characterize the crystal structures and chemical binding of N-doped TiO2. Its photocatalytic activity was examined by the deg- radation of organic compounds. The catalytic activity of the prepared N-doped TiO2 nanoparticles under visible light （λ〉400nm） irradiation is evidenced by the decomposition of 4-chlorophenol, showing that nitrogen atoms in the N-doped TiO2 nanoparticle catalyst are responsible for the visible light catalytic activity. The N-doped TiO2 nanoparticle catalyst prepared with this modified route exhibits higher catalytic activity under UV irradiation in contrast to TiO2 without N-doping. It is suggested that the doped nitrogen here is located at the interstitial site of TiO2 lattice.

Photocatalytic Activity of N-doped TiO2 Photocatalysts Prepared from the Molecular Precursor （NH4）2TiO（C2O4）2

We developed a novel approach for the preparation of N-doped TiO2 photocatalysts by calcining ammonium titanium oxalate at different temperatures. The structures of N-TiO2 were characterized by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, diffuse reflectance UV-Vis spectroscopy, and scanning electron microscope. The N-doped TiO2 photocatalysts calcined below 700 ℃ are the pure anatase phase but that calcined at 700 ℃ is a mixture of anatase and rutile phases. The doped N locates at the interstitial site of TiO2 which leads to the narrowing of bad gap of pure anatase N-TiO2. Among all photocatalysts, N-TiO2 photocatalysts calcined at 600 and 400 ℃ exhibit the best performance in the photodegradation of methyl orange under the UV light and all-wavelength light illuminations, respectively; however, because of the perfect crystallinity and the existence of anatase-rutile phase junctions, N-TiO2 photocatalyst calcined at 700 ℃ exhibits the highest specific photodegradation rate, i.e., the highest quantum yield, under both the UV light and all-wavelength light illuminations.