Preparation of N and Zr co-doped TiO2 The as-prepared NTA was mixed with urea (mass ratio of 1:2) and dissolved in a 2% aqueous solution of hydrogen peroxide, followed by the addition of pre-calculated amount of Zr(NO3)4 · 5H2O (Zr/Ti atomic ratio, 0%, 0.1%, 0.3%, 0.6%, 1.0%, 5.0%, and 10%). The resultant mixed solution was refluxed for 4 h at 40°C and followed by a vacuum distillation at 50°C to obtain the product of x% Zr/N-NTA. Final Zr/N co-doped TiO2 were prepared by the calcination of x% Zr/N-NTA at a temperature range of 300°C to 600°C for 4 h. The target
nanosized TiO2 powder was obtained, denoted as x% Zr/N-TiO2(temperature), for example 0.6% Zr/N-TiO2(500). For reference, Degussa P25 TiO2 powders were used as precursor under the same conditions FK228 solubility dmso Selleckchem Thiazovivin to prepare Zr/N co-doped TiO2 (denoted as Zr/N-TiO2(P25)). Characterization The phase composition of various Zr/N co-doped TiO2 samples were analyzed by X-ray diffraction (XRD, Philips X’Pert Pro X-ray diffractometer; Cu-Kα radiation, λ = 0.15418 nm). The morphologies of samples were observed using a transmission electron microscopy (TEM, JEOL JEM-2100,
accelerating voltage 200 kV). Nitrogen adsorption-desorption isotherms were measured at 77 K on a Quantachrome SI automated surface area and pore size analyzer. The Brunauer-Emmett-Teller (BET) approach was used to evaluate specific surface area from nitrogen adsorption data. The UV-visible diffuse
reflectance spectra (DRS) of the samples were obtained on a UV–vis spectrophotometer (Shimadzu U-3010, Kyoto, Japan) using BaSO4 as the reference. The surface composition of the nanocatalysts was analyzed by X-ray photoelectron spectroscopy (XPS) on a Kratos Axis Ultra System with monochromatic Al Ka X-rays (1486.6 eV). An Axis Ultra X-ray photoelectron spectroscope (Quantera) was used for the chemical characterization of photocatalyst samples. The binding energies (BE) were normalized to the signal for adventitious carbon at 284.8 eV. The photoluminescence (PL) spectra were recorded on a fluorescence spectrometer (fluoroSE). Visible light photocatalytic activity The photocatalytic activities of various Zr/N co-doped else TiO2 samples were evaluated by monitoring the oxidation process of propylene under visible light irradiation. About 25 mg of each photocatalyst sample was spread on one side of a roughened glass plate (ca. 8.4 cm2 active area) and kept in a flat quartz tube reactor. A 300-W xenon lamp (PLS-SXE300/300UV, Beijing Trusttech Co. Ltd., China) was used as the visible light source. A cut filter (λ ≥ 420 nm) was placed between the xenon lamp and reactor. The intensity of visible light irradiated on to be tested samples was ca.17.6 mW · cm−2. Pure C3H6 (99.99%) stored in a high-pressure cylinder was used as the feed gas, and the flow rate of the feed gas was adjusted to 150 mL/h.