ABSTRACT
A series of graphitic carbon nitride/bismuth niobate (g-C3N4/Bi5Nb3O15) heterojunctions with g-C3N4 doping level of 10-90 wt% were prepared by a facile milling-heat treatment method. The phase and chemical structures, surface compositions, electronic and optical properties as well as morphologies of the prepared g-C3N4/Bi5Nb3O15 were well-characterized. Subsequently, the photocatalytic activity and stability of g-C3N4/Bi5Nb3O15 were evaluated by the degradation of aqueous methyl orange (MO) and 4-chlorophenol (4-CP) under the visible-light irradiation. At suitable g-C3N4 doping levels, g-C3N4/Bi5Nb3O15 exhibited enhanced visible-light photocatalytic activity compared with pure g-C3N4 or Bi5Nb3O15. This excellent photocatalytic activity was revealed in terms of the extension of visible-light response and efficient separation and transportation of the photogenerated electrons and holes due to coupling of g-C3N4 and Bi5Nb3O15. Additionally, the active species yielded in the pure g-C3N4- and g-C3N4/Bi5Nb3O15-catalyzed 4-CP photodegradation systems were investigated by the free radical and hole scavenging experiments.
Subject(s)
Bismuth/chemistry , Graphite/chemistry , Niobium/chemistry , Nitriles/chemistry , Water Pollutants, Chemical/chemistry , Azo Compounds/chemistry , Bismuth/radiation effects , Catalysis , Chlorophenols/chemistry , Coloring Agents/chemistry , Graphite/radiation effects , Light , Niobium/radiation effects , Nitriles/radiation effects , Photochemical ProcessesABSTRACT
Plate- and octahedron-like Pt/Bi5Nb3O15 heterostructures are controllably prepared by a hydrothermal treatment method combined with photodeposition in the presence of different surfactants, i.e., cetyltrimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP). The composition, structure, morphology, optical absorption properties, and textural properties of as-prepared Pt/Bi5Nb3O15 are well-characterized, and their simulated sunlight and visible-light photocatalytic activity is evaluated by the degradation of two typical organic pollutants, i.e., methyl orange (MO) and p-nitrophenol (PNP). Special attention is paid to investigate and explain the influence of the morphologies on the photocatalytic activity of the heterostructured Pt/Bi5Nb3O15.
ABSTRACT
A series of mesoporous sulfated zirconia materials functionalized by alkyl-bridged organosilica moieties (SO(4)(2-)/ZrO(2)-SiO(2)(R) with various S/Si or Zr/Si molar ratios and R=CH(2)CH(2) or C(6)H(4)) were developed by a one-step co-condensation technique combined with hydrothermal treatment with the aid of a triblock copolymer surfactant (P123). The structures, morphologies, porosities, and acid properties of the materials were well characterized. Subsequently, the catalytic performances (activity and stability) of SO(4)(2-)/ZrO(2)-SiO(2)(R) were evaluated by the transesterification of both pure triglyceride (tripalmitin) and low-cost virgin plant oil (Eruca sativa Gars. oil) with methanol for biodiesel production under mild conditions (atmospheric pressure, 65 °C), and the enhanced catalytic activity with respect to alkyl-free sulfated zirconia was obtained. This excellent catalytic activity was explained in terms of the inherent Brønsted acidity, well-defined mesoporosity, and increased hydrophobicity of the as-prepared, hybrid, solid acid catalyst.
Subject(s)
Alkanes/chemistry , Biofuels , Organometallic Compounds/chemical synthesis , Organosilicon Compounds/chemistry , Sulfates/chemistry , Zirconium/chemistry , Biofuels/supply & distribution , Catalysis , Hydrophobic and Hydrophilic Interactions , Organometallic Compounds/chemistry , Porosity , Spectroscopy, Fourier Transform InfraredABSTRACT
Heterostructured metallic silver-layered bismuth niobate two-component system (Ag/Bi(5)Nb(3)O(15)) was developed for the first time by a mild hydrothermal method combined with photodeposition. The Ag/Bi(5)Nb(3)O(15) exhibited single-crystalline orthorhombic structure with small particle size (50-200 nm) and octahedral as well as sheet-like shape; additionally, it possessed photoresponse in both UV and visible region. As a novel alternative photocatalysts to TiO(2), the photocatalytic activity of the Ag/Bi(5)Nb(3)O(15) was evaluated by the degradation of tetrabromobisphenol A, a member from the family of the brominated flame retardant, under solar simulating Xe lamp irradiation, and enhanced photocatalytic activity in compared to Bi(5)Nb(3)O(15) itself and Degussa P25 was obtained.
