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In this article, the erbium nitrate pentahydrate (Er(NO3)3·5H2O), tetrabutyl titanate (C16H36O4Ti), glacial acetic acid (CH3COOH), and anhydrous ethanol (C2H5OH) were used as the main raw materials. The Er2Ti2O7 was successfully prepared by the sol-gel method. The structure and morphology of the samples were characterized by thermogravimetric-differential thermal analyzer (TG-DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). The 10 mg/L methyl orange solution was used as a simulated pollutant under UV light conditions. The effects of different temperatures and light times on the photocatalytic performance of the Er2Ti2O7 samples were investigated. The results showed that the pure Er2Ti2O7 samples could be successfully prepared by calcination in the temperature range of 750–1000 °C. The average grain size of Er2Ti2O7 was about 20–60 μm, and the photocatalytic performance of Er2Ti2O7 samples calcined at 900 °C was the best. When the illumination time is 90 min, the degradation rate of methyl orange reaches to about 100%. The preparation of Er2Ti2O7 by the sol-gel method is a kind of ultraviolet light photocatalyst with wide application prospects. [ABSTRACT FROM AUTHOR]

Using citric acid (C6H8O7·H2O), thulium oxide (Tm2O3), nitric acid (HNO3), tetrabutyl titanate (C16H36O4Ti) as main raw materials, the Tm2Ti2O7 samples were successfully prepared by sol-gel method. The prepared samples were characterized by the thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Using 50 mg/L azo dye methyl orange solution as the simulated sewage, the photocatalytic activity of Tm2Ti2O7 samples was investigated at different calcination temperatures and illumination times. The experimental results show that pure Tm2Ti2O7 samples can be prepared at a calcination temperature of 750–1000 °C. According to SEM analysis, Tm2Ti2O7 samples is irregular, with an average particle size of approximately 10 μm. The degradation rate of methyl orange of each sample calcined at 750–1000 °C temperature range can reach more than 50% when exposed to ultraviolet light for 30 min, and the sample calcined at 900 °C has the best photocatalytic effect. When it degrades 50 mg/L methyl orange for 90 min, the degradation rate can almost reach 100%, and the degradation kinetic constant is 0.0488 min−1, which conforms to the first-order kinetics. The above conclusions indicate that Tm2Ti2O7 is a novel photocatalyst with broad application prospects in the field of ultraviolet photocatalysis. [ABSTRACT FROM AUTHOR]

Using poly (ethylene oxide)-poly (propylene oxide)- poly (ethylene oxide) (P123), tetraethyl silicon (TEOS), HCl, n-butanol as raw materials, SBA-15 template was prepared by liquid phase reaction method. Using SBA-15 as template, Cu(NO3)2·3H2O and Co(NO3)2·6H2O as raw materials and n-hexane as solvent, mesoporous CuCo2O4 composite metal oxide was prepared by hard template nano-casting. The composite metal oxides were characterized by thermo gravimetric differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Taking benzyl alcohol as the target, the effects of reaction temperature, different catalyst dosage, reaction time and molar ratio of benzyl alcohol to hydrogen peroxide on selective oxidation of benzyl alcohol by CuCo2O4 were studied, and the oxidation products were analyzed by high performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). The results show that the sample of CuCo2O4 metal composite calcined at 700 °C has the highest purity, and the average particle size is about 500 nm. The optimum conditions for selective oxidation of benzyl alcohol by CuCo2O4 are reaction system temperature of 80 °C, catalyst dosage of 8 g/L, reaction time 3h, the molar ratio 1:1 of hydrogen peroxide to benzyl alcohol. Under the optimum condition, the conversion rate of benzyl alcohol is 78.13% and the recovery rate of benzaldehyde is 56%. Mesoporous CuCo2O4 is a composite metal oxide with good selective oxidation of benzyl alcohol, which has a wide application prospect. [ABSTRACT FROM AUTHOR]

Using citric acid (C6H8O7·H2O), samarium nitrate (Sm(NO3)3·6H2O) and cobalt nitrate (Co(NO3)3·6H2O) as main raw materials, the SmCoO3 samples were successfully prepared by sol-gel method. The prepared samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Using azo dye methyl orange solution as the simulated sewage, the photocatalytic activity of SmCoO3 samples was explored at different synthesis temperatures and illumination times. The experimental results show that pure SmCoO3 samples can be prepared at a calcination temperature of 600 °C to 1000 °C. Under ultraviolet light conditions, the sample of SmCoO3 calcined at 800 °C has the best photocatalytic activity. When illumination times is 120 min, the degradation rate of methyl orange of 10 mg/L can reach more than 97%, and SmCoO3 shows good photocatalytic performance. [ABSTRACT FROM AUTHOR]

Using europium trioxide(Eu2O3), ammonium metavanadate(NH4VO3), nitric acid, ammonium hydroxide and citric acid hexahydrate, the EuVO4 was prepared by hydrothermal method. The structure and morphology of samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and UV-visible diffuse reflectance spectroscopy (DRS). Using methyl orange as simulated sewage, the visible-light photocatalytic activities of EuVO4 were investigated on synthesis temperatures and illumination time. The results showed that the purely rare earth perovskite structure EuVO4 was prepared in the range of hydrothermal temperature of 120 ∼ 180 °C. The EuVO4 particles are uniform size prepared in 140 °C, which have a particle size of 2 ∼ 4 μm and an optical band gap of 2.07 eV. The photocatalytic experiment demonstrates that hydrothermal synthesis at 140 °C is the best. Under visible-light irradiation, the degradation rate methyl orange of 10 mg/L can reach 93% for 60 min. The EuVO4 shows excellent photocatalytic activities. [ABSTRACT FROM AUTHOR]

Using gadolinium nitrate, cobalt acetate, citric acid as main raw materials, GdCoO3 was successfully prepared by sol-gel method. The prepared samples were characterized by thermogravimetric differential scanning analysis (TG-DSC), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy(FT-IR). Using methyl orange solution as simulated sewage, it was investigated that the effects of synthesis temperature and illumination time on photocatalytic activity of GdCoO3. The results show that the pure cubic perovskite GdCoO3 samples can be prepared at calcination temperature of 700 °C to 1000 °C. The GdCoO3 calcined at 900 °C has uniform particles and an average grain size of about 0.5 μm to 1 μm. The photocatalytic performance of GdCoO3 calcined at 900 °C sample was the best. Under the condition of UV-light for 120 min, the photocatalytic degradation rate of methyl orange reached more than 96% in presence GdCoO3 calcined at 900 °C. This indicates that GdCoO3 has good photocatalytic performance. [ABSTRACT FROM AUTHOR]

The TiO2/Fe3O4 composite is a new kind of photocatalytic materials with magnetism. Using FeCl2, FeCl3, and titanyl sulfate as the main raw material, TiO2/Fe3O4 was synthesized by sol-gel process and 450 °C calcination for 2 h under a condition of hydrogen nitrogen mixture gas. The samples were characterized by powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The photocatalytic activity, reclaim and cyclic utilization of the TiO2/Fe3O4 composite were studied by using Rhodamine B as simulated wastewater. The results show that TiO2/Fe3O4 composite has good magnetic properties and excellent photocatalytic activity for removal of Rhodamine B from water, and it can come true well reclaim and recycling by using the electromagnet. The recovery efficiency of TiO2/Fe3O4 composite can reach above 90% at the first reclaiming. TiO2/Fe3O4 composite can be reused tree times without a significant photoactivity loss. It shows that TiO2/Fe3O4 composite is a kind of environmental photocatalyst with a wide application prospects. [ABSTRACT FROM AUTHOR]

TmVO4 precursor gel was prepared by sol-gel method using thulium oxide, nitric acid, ammonium metavanadate and citric acid as main raw materials. Then the xerogel was calcined at 600–800 °C in muffle furnace to prepare TmVO4. The prepared samples were characterized by thermogravimetric differential scanning analysis (TG-DSC), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy(DRS) and Fourier transform infrared spectroscopy(FT-IR). The visible-light photocatalytic activity of TmVO4 was studied by using methylene blue solution as simulated wastewater. The result shows that TmVO4 can be obtained by calcination at 700 °C. The average grain size is about 80 nm and the bandgap is 2.16 eV. Under visible-light conditions, the degradation rate of methylene blue can reach more than 90% when methylene blue solution of 10 mg/L was illuminated 60 min in the presence of nanoparticulate TmVO4. The nanoparticulate TmVO4 has excellent photocatalytic degradation activity for methylene blue. Nanoparticulate TmVO4 prepared by sol-gel method has broad application prospects in photocatalytic degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Using praseodymium nitrate (III) hexahydrate (Pr(NO3)3·6H2O), ammonium metavanadate (NH4VO3) and hexadecyl trimethyl ammonium bromide (CTAB) as raw materials, PrVO4 samples were successfully prepared by hydrothermal method. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential scanning calorimetry (TG-DSC), UV–visible diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The effect of different synthesis temperature and illumination time on the ultraviolet photocatalytic activity of PrVO4 samples was studied with methyl orange solution as simulated sewage. The results show that the pure tetrahedral zircon structure of the PrVO4 sample can be obtained at a hydrothermal temperature of 100–180 °C. The sample of PrVO4 prepared by hydrothermal temperature at 140 °C was uniform, with an average particle diameter of 50–60 nm and a band gap width of 3.1 eV. The photocatalytic experiment demonstrates that the degradation rate of 100 mg/L methyl orange is nearly 92.4% in the presence of PrVO4 sample prepared at 140 °C after UV irradiation at 30 min. The PrVO4 samples show excellent photocatalytic performance for degradation of methyl orange. [ABSTRACT FROM AUTHOR]

Perovskite rare-earth ferrate PrFeO3 is a new kind of photocatalytic material. Using Fe(NO3)3·9H2O, Pr(NO3)3·6H2O, citric acid and urea as main raw materials, the gel of PrFeO3 was prepared by sol–gel method. The gel was kept at 80 °C for 48 h to make xerogel. Then, the xerogel was calcined in muffle furnace at 800 °C to obtain PrFeO3 samples. The structure and morphology of samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and UV–visible diffuse reflectance spectroscopy (DRS). The results showed that the perovskite structure PrFeO3was obtained through sol–gel method. The resulting products have a particle size of 80 nm and an optical band gap of 2.4 eV. Consequently, the PrFeO3 nanoparticles showed high photocatalytic activities for decomposition of methyl orange under visible-light irradiation. The PrFeO3 samples are consistent with first-order kinetics for the degradation of methyl orange. And the apparent rate constants is k = 0.071 min−1. [ABSTRACT FROM AUTHOR]

Nitrogen-rich carbon material derived from carbon self-repairing g-C3N4 is self-assembled with graphene oxide (GO) to form a porous structure. Different from the pristine g-C3N4, which has scarcely been employed in supercapacitors because of its low charge mobility, the carbon self-repairing g-C3N4 (C-C3N4) shows an improved electrochemical activity. After carbon-repairing, a delocalized big π-bond can be formed by the homogeneous C-substitution for N atoms or the formation of new interstitial C–N bond. The extending π-conjugation planar layer of C-C3N4 possesses a closer contact with GO to form a three-dimensional (3D) pore structure, which ensures good mobility for electrons and quick access for electrolytes. Under the optimum C-repairing content of 5.99 at%, the C-C3N4@rGO exhibited high specific capacity of 379.7 F g−1 and energy density of 52.7 W h kg−1 at a current density of 0.25 A g−1. Moreover, the electrode kept 85% capacity retention after 10 000 cycles at a high constant current density of 10 A g−1. The active sites of pseudocapacitance can be confirmed in the oxygen-containing groups and the carbon atoms close to the nitrogen by the XPS results. [ABSTRACT FROM AUTHOR]