Qian Deng

Novel visible light responsive Ag@(Ag2S/Ag3PO4) photocatalysts: synergistic effect between Ag and Ag2S for their enhanced photocatalytic activity

Novel composite photocatalysts, Ag@(Ag2S/Ag3PO4), have been synthesized by controlled calcination and exhibited much higher activity than that of Ag3PO4, Ag2S/Ag3PO4, Ag/Ag3PO4 and AgX/Ag3PO4 (X = Cl, Br and I) in degradation of rhodamine B. The excellent activity is ascribed to the synergistic effect between Ag and Ag2S.

Preparation, Characterization, and Photocatalytic Performance of NdPW12O40/TiO2 Composite Catalyst

Abstract The NdPW12O40/TiO2 composite catalyst was prepared by the sol-gel method and characterized by thermogravimetric-differential thermal analysis, infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, fluorescence emission spectroscopy, scanning electron microscopy, and X-ray diffraction. The photocatalytic eliminations of acetone and methanol were used as model reactions to evaluate the photocatalytic activity of the composite catalyst under ultraviolet light irradiation. The results show that TiO2 modified by NdPW12O40 has small crystal size (11 to 14 nm) and large surface area, and the aggregation of TiO2 particles is effectively inhibited. When the initial concentration of acetone is 6.58 g/m3 and the space time is 2.4 s, the mineralization rate is 96.74% using 0.1 g of 1% NdPW12O40/TiO2 as the catalyst, which conforms to the requirements of emission standards for air pollutants. Methanol can be mineralized completely when its initial concentration is 8.82 g/m3 and the space time is 2.0 s. Compared with pure TiO2, the light absorption ability of NdPW12O40/TiO2 gets enhanced, and the absorption region extends to long wavelengths by 20 nm.

Catalytic performance and kinetics of Au/γ-Al2O3 catalysts for low-temperature combustion of light alcohols

Abstract Au/γ-Al 2 O 3 catalysts were prepared by deposition-precipitation method for the catalytic combustion of low concentration alcohol streams (methanol, ethanol, iso-propanol and n -propanol). The catalysts were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and energy dispersive X-ray micro analysis (EDS) techniques. The XPS results showed that there was only Au 0 on the surface of catalysts. The XRD patterns showed that Au was presumably highly dispersed over γ-Al 2 O 3 . The temperatures for complete conversion of methanol, ethanol, iso-propanol and n -propanol with concentration of 2.0 g/m 3 were 60, 155, 170 and 137 ?, respectively, but they were completely mineralized into CO 2 and H 2 O at 60, 220, 260 and 217 ? respectively over the optimized catalyst. The activity of the catalyst was stable in 130 h. The kinetics for the catalytic methanol elimination followed quasi-first order reaction expressed as r =0.652 8 c 0 +0.084 2. The value of apparent activation energy is 54.7 kJ/mol in the range of reaction temperature.

A novel Anderson-type polyoxometalate: hydrothermal synthesis, crystal structure, and catalytic performance of (H3O)[(3-C5H7N2)2(Cr(OH)6Mo6O18)] · 3H2O

A new Anderson polyoxometalate (H3O)[(3-C5H7N2)2(Cr(OH)6Mo6O18)] · 3H2O (3-C5H6N2 = 3-aminopyridine) was hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Crystal data: triclinic, P 1, a = 7.8482(8) Å, b = 10.1800(10) Å, c = 10.4103(10) Å, α = 88.031(3)°, β = 78.308(2)°, γ = 88.842(3)°, V = 813.91 Å3, Z = 1, R(F) = 0.0397, wR ref(F 2) = 0.1022, and S = 1.076. The X-ray crystallographic study showed that the structure contains Anderson-type [Cr(OH)6Mo6O18]3− polyoxoanions. The title compound has high catalytic activity for the oxidation of acetone tested in a continuous-flow fixed-bed micro-reactor. When the initial concentration is 18.3 g m−3 in air and the flow velocity is 8.5 mL min−1, the acetone is completely eliminated at 160°C.

Preparation of N-Doped Mesoporous TiO2 Using Nitromethane as Nitrogen Source and Their High Photocatalytic Performance

N-doped mesoporous TiO2 was successfully prepared by using CH3NO2 as the nitrogen source and P123 as template. The materials were characterized by TEM, N2 sorption, XRD, XPS, UV-vis DRS, and TG-DTA techniques. The photocatalytic activity of N-doped TiO2 was tested in elimination of gaseous methanol, formaldehyde, and BTX (benzene, toluene and xylene). The obtained N-doped mesoporous TiO2 materials have better photocatalytic activity than commercial photocatalyst (Degussa P25). Moreover, the N-doped mesoporous TiO2 photocatalysts are easy to prepare and have stable performance, high photocatalytic activity and long lifetime.

La-modified mesoporous TiO2 nanoparticles with enhanced photocatalytic activity for elimination of VOCs

La-modified mesoporous TiO2 were synthesized via a sol–gel route using Pluronic P123 as template. The XRD and TEM results show that La loading favors the formation of anatase with smaller crystal size. The photocatalytic activity of the mesoporous anatase was tested in photocatalytic elimination of VOCs. The photocatalysts exhibited higher activity than that of the commercial photocatalyst (Degussa, P25) under either ultraviolet or visible light irradiation. The superior activity of the mesoporous anatase may be attributed to the synergic effects of the surface area, crystal size and loaded La species.

Syntheses, characterizations and crystal structures of two new complexes, [Co2(CH2 =C(CH3)CO2)4(phen)2(H2O)2] and [Pb2(CH2 =C(CH3)CO2)4(phen)2]

Two new complexes, [Co2(CH2=C(CH3)CO2)4(phen)2(H2O)2] (1) and [Pb2(CH2=C(CH3)CO2)4(phen)2] (phen = 1,10-phenanthroline) (2), have been synthesized and structurally characterized by single crystal X-ray diffraction methods. There are two cocrystallized conformers of [Co(CH2=C(CH3)CO2)2(phen)(H2O)] in the asymmetric unit of 1 with the Co atoms displaying similar coordination modes. In the asymmetric unit of 2, there exist two crystallographically independent [Pb(CH2=C(CH3)CO2)2(phen)] molecules with the Pb atoms showing completely different coordination geometries. Weak intermolecular interactions such as hydrogen bonding and π–π stacking are responsible for the supramolecular assembly and stabilization of the crystal structures of 1 and 2. The complexes are characterized by elemental analysis, IR spectra, and UV–Vis spectra. The fluorescent properties of 2 are also discussed.

Syntheses, Crystal Structure, Characterization, and Properties of Two Novel Superamolecular Phosphotungstate-Pyridine Complexes

Two new inorganic-organic compounds constructed from phosphotungstate and pyridines have been synthesized under hydrothermal conditions. The formulas of the two compounds are (C5H7N2)3(C5H6N2)3(PW12O40)·2H2O (1) and (C6H8N)3(C6H7N)(PW12O40)·9H2O (2). They have been characterized by IR, UV-vis, TG-DTA, FL, CV, and single-crystal X-ray diffraction. The two compounds both show three-dimensional networks. These compounds exhibit good catalytic activity for catalytic oxidation of methanol over a continuous-flow fixed-bed microreactor, when the initial concentration of methanol is 5.37 g⋅m−3, and flow rate is 4.51 mL⋅min−1. 0.2 g compound 1 (or compound 2) as the catalyst can eliminate methanol completely at 150°C (175°C for compound 2).

Two multifunctional organic-inorganic hybrid complexes based on polyoxometalates, BiEDTA and sodium linker: crystal structures, photochromic, and catalytic performances

Abstract Two 3-D organic–inorganic hybrid supermolecular complexes, Na(BiHEDTA·2H2O)3(PW12O40)·2H3O (BiPW) and Na(BiHEDTA·2H2O)3(PMo12O40)·2H3O·2H2O (BiPMo) ethylenediamine tetraacetic acid (EDTA) have been synthesized by solution method and characterized by ultraviolet visible (UV–vis) spectroscopy, thermogravimetric-differential thermal analysis, photoluminescence, cyclic voltammetry, and single-crystal X-ray diffraction (XRD). XRD analysis reveals that BiPW and BiPMo are isostructural with 3-D architectures assembled by 2-D layer tetranuclear cation and a Keggin-type polyoxoanion. Although these two hybrids exhibit similar structures, the properties depend on the nature of polyoxoanion [PM12O40]3− (M = W, Mo). Under UV irradiation, BiPW and BiPMo show fast response of reversible and irreversible photochromism, respectively. BiPW exhibits excellent photocatalytic activity in degradation of methyl orange dyes under irradiation of UV–visible light. It can be reused for at least six cycles without obvious loss of activity in the degradation experiments; BiPMo shows catalytic activity in elimination of methanol. The elimination rate of methanol reaches 56.9% when the concentration of methanol is 2.3 g·m−3 and the flow velocity is 10 mL·min−1 at 100 °C.

Crystal Structure and Blue Fluorescence of a New Inorganic-Organic Hybrid Polyoxometalate (3-C6H8N)4(PMo12O40)·H2O

One new supramolecular structure organic-inorganic hybrid compound (3-C6H8N)4(PMo12O40)·H2O constructed by phosphomolybdate and 3-methylpyridine via hydrogen bond and π-π stacking interactions was obtained by hydrothermal reaction and characterized by IR, UV-vis, TG-DTA, FL, CV, and single-crystal X-ray diffraction. The luminescent properties of the compound at room temperature were investigated. The title compound exhibits good thermal stability and blue fluorescence in the aqueous solution at room temperature. The CV curve revealed a pair of irreversible redox wave and two pairs of redox wave, which are one-electron and two-electron quasireversible redox processes of Mo. Supplemental materials are available for this article. Go to the publishers online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.