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Ou M.,Nanjing University of Science and Technology | Ou M.,Nanjing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,Nanjing AIREP Environmental Protection Technology Co. | And 2 more authors.
Journal of Sol-Gel Science and Technology | Year: 2014

Novel visible-light-driven g-C3N4/BiVO4 composite photocatalysts were fabricated via sol–gel and simple mixing and heating methods. The photocatalysts were characterized by X-ray diffraction, thermogravimetric, Fourier transform infrared, transmission electron microscope, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectra. The results indicated that BiVO4 was well dispersed on g-C3N4 sheet and an interaction between g-C3N4 and BiVO4 was confirmed, which were facile to the electron transfer from g-C3N4 to BiVO4 species. The mechanism was further induced to the heterojunction effect to improve the photocatalytic efficiency. The g-C3N4/BiVO4 heterojunction at a weight ratio of 80 % calcined at 500 °C exhibited the most excellent photocatalytic ability for RhB decolorization under visible-light irradiation (λ > 420 nm) which was extraordinary more active than that of pure components. © 2014, Springer Science+Business Media New York.


Cai W.,Nanjing University of Science and Technology | Cai W.,Nanjing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,Nanjing AIREP Environmental Protection Technology Co. | And 2 more authors.
Chemical Engineering Journal | Year: 2014

Cr-doped Ce0.2Zr0.8O2 was synthesized with cinnamic acid as ligand, and four different solvents (H2O, ethanol, ethylene glycol and isopropanol) were added into the precursor solution to contrast with each other. These catalysts were investigated in detail by means of X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, High resolution transmission electron microscope (HR-TEM), Ultra violet-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS) and NO(O2) Temperature-programmed desorption (NO(O2)-TPD). The results indicated that the preparation process adopted with one-step method simplified the experimental procedure, decreased the size of particle and increased the specific surface area of the catalysts. Moreover, the solvent with appropriate polarity could decrease the band gap of the catalysts and benefit for more generation of Ce3+ and Cr6+ on the surface of the catalyst, which was beneficial for the adsorption of NO and O2. All catalysts showed broad activity temperature window and the catalyst adopted with ethylene glycol as solvent exhibited the highest NO conversion, which achieved 66.32% at 350°C. © 2014 Elsevier B.V.


Ding J.,Nanjing University of Science and Technology | Zhong Q.,Nanjing University of Science and Technology | Zhang S.,Nanjing AIREP Environmental Protection Technology Co.
Fuel Processing Technology | Year: 2014

A novel oxidation-removal process for simultaneous removal of NO X and SO2 was developed, which utilized the catalytic ozonation over Ce-Ti catalyst and assisted with a glass made ammonia-based washing tower. Compared with conventional flue gas treatment, the present method acquires non-secondary pollution, minimal waste production and low operating costs. The main byproducts, ammonia sulfate and nitrate, are important fertilizers and industrially raw materials. A maximum removal of 95% for NO X and nearly complete SO2 removal were obtained with the assistance of washing tower under the following experimental conditions: O 3 concentration, 8.5 mg·L- 1; flow of oxidant mixtures, 100 mL·min- 1; simulated flue gas temperature, 120 °C; H2O flow, 2.4 mL·min- 1; and total gas flow, 400 mL·min- 1. The reaction mechanisms are discussed, and the final oxidation products are characterized. The experimental results show that the OH radicals from catalytic ozonation have an oxidation-removal effect of NOX and SO2. The multipollutant capacity of the washing tower is largely enhanced with the Ce-Ti catalyst. And the present method performs better stability with the assistance of the washing tower. © 2014 Published by Elsevier B.V.


Zhong L.,Nanjing University of Science and Technology | Zhong L.,Nanjing AIREP Environmental Protection Technology Co. | Cai W.,Nanjing University of Science and Technology | Cai W.,Nanjing AIREP Environmental Protection Technology Co. | And 2 more authors.
RSC Advances | Year: 2014

A series of cerium modified Cr/Ti-PILC catalysts were evaluated, which showed a remarkable increase in the activity of NO oxidation. The aim of this novel design was to investigate the mechanism of cerium modification over the Cr/Ti-PILC catalyst. Physicochemical characteristics were investigated in detail by various techniques such as BET, TPD (NO and O2), XPS, PL, EPR and DRIFTS. The analysis results demonstrated that cerium modification could facilitate the generation of oxygen vacancy via charge transfer, promote the formation of surface superoxide ions (O2 -), and increase the amount of surface nitrates. Furthermore, the original oxidation pathway of Cr/Ti-PILC was maintained by cerium modification. The experimental results showed that the NO conversion of CrCe(0.25)/Ti-PILC catalyst was increased to nearly 66.9% at 300 °C. This journal is © the Partner Organisations 2014.


Zhang S.,Nanjing University of Science and Technology | Zhang S.,NanJing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,NanJing AIREP Environmental Protection Technology Co. | And 2 more authors.
Applied Surface Science | Year: 2014

A series of V2O5/TiO2 catalysts with different ratios of TiO2 rutile phase was prepared. Focusing on the effect of TiO2 rutile phase on V2O5/TiO 2 catalyst for the selective catalytic reduction (SCR) of NO with NH3, the NO conversion for the different catalysts was investigated. The experimental results showed that a small amount of TiO2 rutile phase could improve the NO conversion significantly below 270 °C. Analysis by XRD, NH3-TPD, UV-vis, EPR and DFT calculation showed that the rutile phase of TiO2 supporter decreased the band gap, especially, the conduction band level. It improved the formation of reduced V species and superoxide ions that were important to the low-temperature SCR reaction. © 2014 Elsevier B.V.


Ding J.,Nanjing University of Science and Technology | Ding J.,Nanjing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,Nanjing AIREP Environmental Protection Technology Co. | And 4 more authors.
Journal of Hazardous Materials | Year: 2015

A novel, simple, reproducible and low-cost strategy is introduced for the size- and shape-controlled synthesis of iron-aluminum mixed oxide nanoparticles (NIAO(x/y)). The as-synthesized NIAO(x/y) catalyze decomposition of H2O2 yielding highly reactive hydroxyl radicals (•OH) for NOX and SO2 removal. 100% SO2 removal is achieved. NIAO(x/y) with Fe/Al molar ratio of 7/3 (NIAO(7/3)) shows the highest NOX removal of nearly 80%at >170•C, whereas much lower NOX removal (<63%) isobtained for NIAO(3/7). The melting of aluminum oxides in NIAO(7/3) promotes t h e formation of lamellar products, thus improving the specific surface areas and mesoporous distribution, benefiting theproduction of• OH radicals. Furthermore, the NIAO(7/3) leads to the minor increase of points of zero charges (PZC), apparent enhancement of FeOH content and high oxidizing ability of Fe(III), further improving the production of •OH radicals. However, the NIAO(3/7) results in the formation of aluminum surface-enriched spherical particles, thus decreasing the surface atomic ratio of iron oxides, decreasing • OH radical production. More importantly, the generation of FeOAl causes the decline of active sites. Finally, the catalytic decomposition of H2O2 on NIAO(x/y) is proposed. And the well catalytic stability of NIAO(7/3) is obtained for evaluation of 30 h. © 2014 Elsevier B.V.


Cai W.,Nanjing University of Science and Technology | Cai W.,Nanjing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,Nanjing AIREP Environmental Protection Technology Co. | And 4 more authors.
Applied Catalysis B: Environmental | Year: 2014

A modified Cr/CexZr1-xO2 with the rigid benzene-muti-carboxylate ligands are prepared and studied on the oxidation of NO. These catalysts were investigated in detail by means of X-ray diffraction (XRD), High resolution transmission electron microscope (HR-TEM), Brunauer-Emmett-Teller (BET) surface area analysis, Ultra violet-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), NO(O2) Temperature-programmed desorption (NO(O2)-TPD) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results demonstrated that the catalysts prepared with cinnamic acid as precipitant showed a higher surface area, a lower band gap and a stronger ability to adsorb reactant gas. Otherwise, the ligands such as terephthalic acid and trimesic acid were unfavorable for the synthesis of CexZr1-xO2 due to the long distance between the carboxyl groups. Furthermore, the π-π conjugated effect of the cinnamic acid balanced the charge in the precursor of the catalysts prepared with cinnamic acid, thus leading to their band gaps lower than that of other catalysts after calcinations. The catalytic performance over the catalysts prepared with cinnamic acid exhibited the highest NO conversion, and the preparation with one-pot method was simpler. Moreover, the catalyst prepared with one-pot method showed well ability to resist the poison effect of H2O and SO2, which was due to the large surface area. Finally, while combined the XPS analysis, in-situ DRIFTS demonstrated that the adsorbed NO interacted with the adsorbed O2 to generate NO2, and the adsorption and activation O2 was the key factor. © 2014 Elsevier B.V.


Ding J.,Nanjing University of Science and Technology | Ding J.,Nanjing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,Nanjing AIREP Environmental Protection Technology Co. | And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2015

Amorphous cerium and titanium mixed oxides (Am-CeTi) and crystalline cerium and titanium mixed oxides (Ct-CeTi), prepared by coprecipitation and impregnation methods, respectively, were successfully utilized in catalytic ozonation for NOx removal. The catalytic activity has been confirmed to be determined by the concentration of ·OH radicals. Am-CeTi shows higher activity than Ct-CeTi. Ce-O-Ti linkage bonds, with an interaction between Ce and Ti on an atomic scale, are confirmed for the first time to be an active site for catalytic ozonation to remove NOx. The incorporation of more Ce results in an amorphous structure (Am-CeTi) and a higher number of Ce-O-Ti linkage bonds as compared to that of Ct-CeTi, and the Ce-O-Ti structure is directly observed by HR-TEM. Moreover, such incorporation is responsible for less surface defects and lower densities of surface hydroxyl groups because of the elimination of crystalline defects. The higher catalytic activity of Am-CeTi indicates the small effect of surface defects and surface groups. © 2015 American Chemical Society.


Ou M.,Nanjing University of Science and Technology | Ou M.,Nanjing AIREP Environmental Protection Technology Co. | Zhong Q.,Nanjing University of Science and Technology | Zhong Q.,Nanjing AIREP Environmental Protection Technology Co. | And 4 more authors.
Journal of Alloys and Compounds | Year: 2015

The visible light active g-C3N4/BiVO4 catalysts were synthesized via facile ultrasonic dispersion and calcination methods and used in the study for photocatalytic oxidation (PCO) of NO in gas phase. The as-synthesized samples were analyzed by various characterization techniques. The results exhibited that an interaction between BiVO4 and g-C3N4 was confirmed and a heterojunction was formed on the surface of g-C3N4/BiVO4 composite, which enhanced the separation and transfer of photogenerated electron-hole pairs. The mechanism on the heterojunction effect to improve the PCO ability was also proposed. The activity test showed that the optimum content of g-C3N4 was 50 wt%. And the maximum conversion of NO was four times larger than that of the pure components when the inlet concentration of NO was about 400 ppm under the visible light (VL) irradiation. The ion chromatography (IC) showed that NO was removed in the oxidation formation of NO2 - and NO3 -. © 2014 Elsevier Ltd. All rights reserved.


Huang X.,Nanjing University of Science and Technology | Huang X.,Nanjing AIREP Environmental Protection Technology Co. | Ding J.,Nanjing University of Science and Technology | Ding J.,Nanjing AIREP Environmental Protection Technology Co. | And 2 more authors.
Applied Surface Science | Year: 2015

Simultaneous flue gas desulfurization and denitrification were achieved with OH radicals from the decomposition of H2O2 over hematite (Fe) as well as hematite supported on alumina (Fe-Al) and anatase (Fe-Ti). Under all conditions, SO2 achieved 100% removal, whereas NOX removal varies with the catalysts. The supporting of Fe over aluminum enhances the catalytic removal of NOX, whereas that of anatase presents negative effect. The NOX removal is determined by the decomposition rate of H2O2 into OH radicals over OH bonded with Fe (Fe-OH). The supporting of Fe over alumina enhances the content of Fe-OH and the points of zero charge (PZC) values, which are beneficial for the production of OH radicals. The supporting of Fe over anatase results in the formation of FeOTi, which cannot decompose H2O2 into OH radicals. Furthermore, H2O2 tends more to be reacted with TiOH to produce O2 over Fe-Ti. Finally, the enhancement mechanism of H2O2 decomposition over Fe-based catalysts is speculated. It has a contribution to the correct choice for supports and active ingredients of the catalyst in the future industrial applications. ©2014 Elsevier B.V. All rights reserved.

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