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.
近年来,基于BiVO_(4)光阳极的光电催化分解水技术引起人们的关注.我们通过水热-氨化法制备出Ni_(3)N纳米颗粒,首次将其作为助催化剂修饰到BiVO_(4)光阳极上光电催化分解水.实验表明, Ni_(3)N纳米颗粒成功负载到BiVO_(4)光阳极表面并可有效抑制表面电荷复合以及提高光电催化分解水性能.在1.23 V v. RHE处光电流密度可达3.23mA/cm^(2).此外, Ni_(3)N/BiVO_(4)光阳极的最大值ABPE值达0.88%,并呈现出良好的稳定性.
Fe based oxides are considered as a promising catalyst for the oxygen evolution reaction （OER） due to their low cost and high stability. Here, based on density functional theory calculations, the electrocatalytic behaviors of pure and metal （Ni, Co） doped Fe-terminated Fe2O3（0001） are investigated. The potential-limiting step for OER is determined as the formation of O＊ by dehydrogenating surface hydroxyl and it is suggested that the doping enhances the catalytic activity of Fe2O3（0001） by reducing the free energy change of rate limiting step on doped Ni or Co atom. Especially, the calculated over-potential of Co-doped Fe2O3 （0001） surface is about 0.63 eV on Co site, which is comparable with the theoretical over-potential of 0.56 eV for RuO2.
