boron and methyl-orange

A B-doped BiVO4 photocatalyst was synthesized by citric acid complex method and using H3BO3 as the dopant source, and the photocatalyst was characterized with XPS, XRD, SEM, BET and UV-Vis DRS. The photocatalytic activity was evaluated by the photocatalytic degradation of a methyl orange (MO) solution under visible light. This assay revealed that both the pure BiVO4 and all of the B doped samples were the monoclinic phase. Doping the BiVO4 with B increased the number of V(4+) and oxygen vacancies, which led to the red shift of the absorbing boundary of the B-doped BiVO4 but had little influence on the morphology and crystal size. The B doping improved the photocatalytic activity, and the highest photocatalytic degradation rate of 98% occurred with a B dopant concentration of 0.04.

Topics: Azo Compounds; Bismuth; Boron; Catalysis; Citric Acid; Light; Photolysis; Vanadates

Eu-B co-doped BiVO4 visible-light-driven photocatalysts have been synthesized using the sol-gel method. The resulting materials were characterized by a series of joint techniques, including XPS, XRD, SEM, BET, and UV-vis DRS analyses. Compared with BiVO4 and B-BiVO4 photocatalysts, the Eu-B-BiVO4 photocatalysts exhibited much higher photocatalytic activity for methyl orange (MO) degradation under visible light irradiation. The optimal Eu doping content is 0.8 mol%. It was revealed that boron and europium were doped into the lattice of BiVO4 and this led to more surface oxygen vacancies, high specific surface areas, small crystallite size, a narrower band gap and intense light absorbance in the visible region. The doped Eu(III) cations can help in the separation of photogenerated electrons. The synergistic effects of boron and europium in doped BiVO4 were the main reason for improving visible light photocatalytic activity.

Topics: Azo Compounds; Bismuth; Boron; Europium; Light; Microscopy, Electron, Scanning; Nanoparticles; Photolysis; Vanadates; Water Pollutants, Chemical

Topics: Azo Compounds; Boron; Catalysis; Electron Spin Resonance Spectroscopy; Environmental Pollutants; Environmental Restoration and Remediation; Fluorine; Methylene Blue; Photochemical Processes; Spectrophotometry, Atomic; Titanium; Ultraviolet Rays; X-Ray Diffraction

Single doped, co-doped and tri-doped TiO(2) with B, N and Fe are successfully synthesized by using the hydrothermal method. The samples are characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples are evaluated for degradation of methyl-orange (MO, 20 mg L(-1)) in aqueous solutions under visible light (lambda > 420 nm). The results of XRD suggest that all the catalysts present anatase crystal. All the doping catalysts show higher photoactivities than pure TiO(2) under visible light irradiation. In the single nonmetal doped TiO(2), the localized dopant levels near the valence band (VB) are responsible for the enhancement of photoactivies. Fe(3+) impurity level formed under the conduction band (CB) induces the high photocatalytic activities of iron doped TiO(2). In the co-doped and tri-doped catalysts, the B 2p and N 2p acceptor states contribute to the band gap narrowing by mixing with O 2p states combined with the overlapping of the conduction band by the iron "d" orbital, resulting in improvement of the photo-performance under visible light irradiation. Iron co-doped with boron catalyst shows low photoactivity under visible light due to the absence of Fe(3+) impurity levels at the bottom of the conduction band. In addition, the XPS results indicate the presence of synergistic effects in co-doped and tri-doped catalysts, which contribute to the enhancement of photocatalytic activities.

Topics: Azo Compounds; Boron; Catalysis; Iron; Light; Nitrogen; Photoelectron Spectroscopy; Photolysis; Spectrophotometry, Ultraviolet; Thermodynamics; Titanium; X-Ray Diffraction