Asia-Pacific Journal of Chemical Engineering
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2019
·Vol. 14
·期 3
·e2309
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IF 1.396
Zulfiqar Ali,Qiang Lu,Tahir Iqbal,Zulqarnain Arain,Jian Han,Yang-wen Wu,Ding-jia Liu,Yong-ping Yang
Heavy metal Pb is an inevitable ingredient of coal-fired flue gas and has been proven to be a source of inhibiting effect on the selective catalytic reduction (SCR) catalyst. In this paper, two types of Pb-poisoned catalyst, prepared by the incipient wetness impregnation and solid diffusion methods, are studied to unveil the poisoning effects of lead species on the V 2 O 5 -WO 3 /TiO 2 catalyst. The activity test results showed that lead species loaded by the incipient wetness impregnation method exhibited a significant inhibiting effect on the denitrification efficiency of the catalyst although a negligible activity loss was observed on the samples from the solid diffusion method. Characterizations of fresh and Pb-poisoned catalysts from incipient wetness impregnation method were applied using comprehensive techniques such as X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray fluorescence (XRF), NH 3 -temperature programmed desorption (NH 3 -TPD), X-Ray photoelectron spectroscopy (XPS), and so forth. The analytical results indicated that a phase transformation occurred in tungsten species and the amorphous WO 3 converted into PbWO 4 , causing the accumulation and valence imbalance of active vanadium phase, which further decreased the surface acidity and activity of the V 2 O 5 -WO 3 /TiO 2 catalyst.
研究领域:
环境科学
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催化材料
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Xiaoyan Zhao,Yongcheng Zhou,Hua Guo,Yuqi Zhai,Xianrui Zou,Donghui Wang
Titanium dioxide (TiO 2 ) has received widespread attention as high stability, low toxicity and costless photocatalyst , but it only exhibits photocatalytic activity under ultraviolet (UV) light. To improve TiO 2 photocatalytic efficiency, Bio-CaCO 3 /WO 3 /TiO 2 /(Ca,Y)F 2 :Tm,Yb was prepared. TiO 2 was combined with upconversion materials, coupled with WO 3 and loaded on oyster shell powder (Bio-CaCO 3 ), which showed that the prepared photocatalyst effectively reduce the band gap of TiO 2 , expand the photoreaction range of the material and avoid agglomeration, thus improving its photocatalytic efficiency and antibacterial efficiency. The photocatalytic degradation efficiency of Bio-CaCO 3 /WO 3 /TiO 2 /(Ca,Y)F 2 :Tm,Yb (50 mg) was 24.32% higher than that of TiO 2 /(Ca,Y)F 2 :Tm,Yb in 90 min. And its antibacterial rates against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) were enhanced by 38.68% and 25.89% compared to TiO 2 /(Ca,Y)F 2 :Tm,Yb, respectively.
研究领域:
材料科学
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环境科学
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生物学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Chong Xia,Yuanqing Zhu,Song Zhou,Yongming Feng,Jie Shi
Besides catalyzing NOx reduction, the V 2 O 5 -WO 3 /TiO 2 catalyst can effectively suppress the formation of urea (CH 4 N 2 O) decomposition by-products in selective catalytic reduction (SCR). However, current research lacks a clear understanding of the impact of urea and its by-products on the catalyst' performance. Additionally, there is no available kinetic model to describe the decomposition process of urea and its by-products on the V 2 O 5 -WO 3 /TiO 2 catalyst. In this paper, the decomposition process of urea and its by-products on the catalyst was firstly investigated via thermogravimetric analysis (TGA). It was found that increasing the catalyst dosage can accelerate urea decomposition and block the transformation pathways from urea and biuret (C 2 H 5 N 3 O 2 ) to cyanuric acid (cya, C 3 H 3 N 3 O 3 ). However, as the decomposition temperature of the by-products increased, a larger amount of catalyst was also required. Secondly, the impact of urea and its by-products on the NOx reduction performance was investigated via the SCR test bench. The results showed that, at 200 ℃, the addition of 20 % urea, biuret, or cya decreased the NOx reduction rate by 7.2 %, 9.8 %, and 11.0 % respectively. Furthermore, the catalyst's performance was significantly improved at 400 ℃ dues to the decomposition of urea and its by-products. Then, various characterization techniques were used to analyze the morphology and chemical composition of the urea decomposition products on the catalyst at different temperatures. On this basis, a simplified urea non-catalytic and catalytic coupling mechanism model was developed, which included 7 species and 16 reactions. Finally, the kinetic parameters of the proposed urea catalytic decomposition model were optimized utilizing TGA test data, density functional theory (DFT), and genetic algorithms (GA). This study can provide guidance for the elimination of SCR urea deposits in engineering applications.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
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2014
·
IF 4.086
Man Zhang,Changzhu Yang,Wenhong Pu,Yuanbin Tan,Kun Yang,Jingdong Zhang
ABSTRACT The heterojunction films of WO 3 /TiO 2 were prepared by liquid phase deposition (LPD) method via two-step processes. The scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopic analysis indicated that flower-like WO 3 film was successfully deposited on TiO 2 film with the LPD processes. The TiO 2 film provided an excellent platform for WO 3 deposition while WO 3 obviously expanded the absorption of TiO 2 film to visible light. As the result, the heterojunction film of WO 3 /TiO 2 exhibited higher photocurrent response to visible light illumination than pure TiO 2 or WO 3 film. The photoelectrocatalytic (PEC) activity of WO 3 /TiO 2 film was evaluated by degrading Rhodamin B (RhB) and 4-chlorophenol (4-CP) under visible light irradiation. The results showed that the LPD WO 3 /TiO 2 film possessed high PEC activity for efficient removal of various refractory organic pollutants.
研究领域:
材料科学
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环境科学
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光电催化
✓ 已验证
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2022
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IF 5.477
Kaiwen Ni,Yuewang Peng,Geyu Dai,Huawang Zhao,Zhiwei Huang,Xiaomin Wu,Guohua Jing,Wei Feng,Ye Yuan
Background Ammonia bisulfate (ABS) deposition on the active sites of the catalyst surface is the main reason for SO 2 poisoning in low-temperature NH3-selective catalytic reduction (SCR). Accelerated ABS decomposition efficiently enhances the SO 2 resistance. Methods In this work, ceria was specifically chosen to decorate V 2 O 5 -WO 3 /TiO 2 catalyst (Ce-VW/Ti) to activate ABS decomposition in low-temperature NH 3 -SCR. Significant findings The optimal 7Ce-VW/Ti catalyst accelerated the decomposition of ABS and had superior SO 2 tolerance at 250°C. The additive CeO 2 improved the specific surface area and surface acidity, favoring the NH 3 -SCR catalytic activity. ABS was preferentially deposited on the additive CeO 2 on the surface of the 7Ce-VW/Ti catalyst and generated cerium sulfate, eventually protecting the active V 2 O 5 sites and TiO 2 support. Moreover, high quantity of V 5+ and charge transfer between active species V 2 O 5 and support TiO 2 could be maintained due to CeO 2 protection, subsequently maintaining the high NH 3 -SCR performance and enhancing the SO 2 tolerance.
研究领域:
催化
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2021
·Vol. 11
·期 4
·445
·
IF 4.146
Yangyang Guo,Xiaofei Xu,Hong Gao,Yang Zheng,Lei Luo,Tingyu Zhu
Ca poisoning behavior is inevitable for high-calcium content flue gas, so V2O5-WO3/TiO2(VWT) and V2O5-WO3-CeO2/TiO2(VWCeT) catalysts with different vanadium content have been prepared and the Ca-doped catalysts are compared in this manuscript. The result shows Ce addition can both promote the NO conversion and the alkali resistance. Lower Ca addition for 0.1VWCeT catalyst promotes its oxidability and Ce modification is more suitable for low vanadium catalysts. The total acidity and the reducibility of catalysts decline after Ca doping, and the reducibility of the active species on catalysts has been strengthened by Ce addition. CeO2based catalysts with lower Ca loading struggle to resist sulfur poisoning, while higher Ca loading favors SO2adsorption and also physically reduces the cerium acidification process. In the presence of SO2, additional Brønsted acid sites are formed in Ca rich catalyst. The dynamic NH3adsorption has been investigated, shows that Ca doping content on catalyst is critical for SCR reaction, and the catalyst is more susceptible to SO2initially in alkali flue gas during the actual application, but the sulfur resistance may increase with the alkali-poisoning effect aggravated by Ca doping.Keywords:Ca-poisoning;SCR reaction;NO reduction;V2O5-WO3/TiO2and V2O5-WO3-CeO2/TiO2catalysts;SO2and water;NO removal efficiency
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
Tungsten
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2024
·
IF 5.6
Zhang Zhi-Qi,Yang Liu,Luo Wen,An Vladimir,Li Jing,Liu Bao-Dan
The design and synthesis of vanadium-based denitration catalysts with low-temperature activity pose significant challenges in the field of toxic gas catalysis. In this study, we have developed a novel approach to fabricate highly efficient V 2 O 5 -WO 3 /TiO 2 monolithic mesh catalysts for NO x reduction at low temperatures. First, TiO 2 nanosheets with strong adhesion and large surface area were grown on Ti mesh using plasma electrolytic oxidation technology and hydrothermal method. Then, super-small traces of WO 3 and V 2 O 5 active nano-species were subsequently deposited on TiO 2 nanosheets using the deposition–precipitation method. Compared to traditional ceramic-based V 2 O 5 -WO 3 /TiO 2 catalysts, our V 2 O 5 -WO 3 /TiO 2 monolithic mesh catalyst exhibits superior mechanical performance, excellent thermal conductivity, lower pressure drop, higher utilization of active components, and stronger synergistic effects. Significantly, the V 2 O 5 -WO 3 /TiO 2 monolithic mesh catalysts exhibited excellent low-temperature catalytic activity with 98% of NO x conversion at 220 ℃, and remarkable long-term SO 2 tolerance and water resistance in the selective catalytic reduction (SCR) of NO x with NH 3 . The SCR reaction of tiny V 2 O 5 and WO 3 active species supported on TiO 2 nanosheets directly demonstrated to follow the Eley–Rideal mechanism by in situ infrared spectra.
研究领域:
催化
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Zhixiang Ren,Ao Li,Xinyu Lei,Zhengwei Yu,Guangying Wang,Hongliang Zhang,Huan Chen,Yin Wang,Hongming Long
As a mainstream moderate-high temperature (250–420 °C) particulate denitrification catalyst, V 2 O 5 -WO 3 /TiO 2 (VWT) is not applicable to low-temperature (60–150 °C) iron ore sintering flue gas after semi dry/wet desulfurization. In order to improve the NH 3 -deNO x performance of the VWT particle catalyst at low temperatures, a series of powder VWT denitrification catalysts doped with different content of RuO 2 (R-VWT) prepared by the wet co-impregnation method were researched, and found that the particulate catalyst service temperature (about 100 % NO conversion) is lowered from 225 °C (VWT) to below 175 °C by doping 0.5 % RuO 2 . In addition, a series of characterizations indicate that the doped RuO 2 enhances the redox performance of R-VWT and promotes the generation of more surface active intermediate monodentate nitrate, and accelerates the low-temperature surface SCR transient reaction rate.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Li Cao,Xiaodong Wu,Ze Chen,Yue Ma,Ziran Ma,Rui Ran,Zhichun Si,Duan Weng,Baodong Wang
CeO 2 /WO 3 -TiO 2 (CeWTi) and Nb 2 O 5 -CeO 2 /WO 3 -TiO 2 (NbCeWTi) catalysts were prepared by a sol-gel precipitation method. Both the catalysts exhibit high selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) activities at 270–500 °C. The sulfur tolerances of the catalysts were evaluated at 270 °C by adding H 2 O and SO 2 in the feeding gas and NbCeWTi exhibited a significantly improved resistance. The thermogravimetric (TG) and mass spectrographic (MS) results indicated that much less sulfates formed on NbCeWTi and existed mainly in the form of ammonium hydrogen sulfate species which protected Ce x+ active sites effectively from attacking of SO 2 . According to the results of temperature-programmed desorption of ammonia (NH 3 -TPD), H 2 temperature-programmed reduction (H 2 -TPR) and SO 2 oxidation , loading niobia on CeWTi inhibited the SO 2 oxidative adsorption and SO 3 production which basically reduced sulfur poisoning of the catalyst. Additionally, the niobia modification ensured the formation of nitrates from the competitive adsorption of SO 2 and hereby facilitated the nitrate SCR route based on the in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS).
研究领域:
催化
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2018
·
IF 6.434
Jingsong Han,Yue Li,Liming Yang,Tingting Li,Yan Luo,Lixia Yang,Shenglian Luo
The suitable doping or modification on TiO 2 holds promise for improving charge separation and extending light absorption range. Here, WO 3 modifying reduced band gap mesoporous TiO 2 (WO 3 /RM-TiO 2 ) due to WO 3 doping was successfully fabricated by immersing mesoporous TiO 2 nanoparticles in the peroxotungstic acid sol with controllable reaction time (0–1 h). The W 6+ ions were first incorporated into the TiO 2 lattice to form W O Ti bonds, resulting in the formation of WO 3 doping TiO 2 . Then, WO 3 nanoparticles gradually formed and attached on the TiO 2 surface, constructing a novel heterojunction catalyst with WO 3 serving as both dopant and light-sensitizer for TiO 2 . Photocatalytic activity of the resulting WO 3 /RM-TiO 2 depends on the immersing duration in the peroxotungstic acid. The BET analysis shows that 0.5 h-WO 3 /RM-TiO 2 has the largest pore volume of 0.491 cm 3 g −1 and the highest surface area of 82.3 m 2 g −1 , whereas these values decline with prolonged immersing duration. As expected, the optimal efficiency in removing p-nitrophenol (PNP) is achieved over 0.5 h-WO 3 /RM-TiO 2 under visible light irradiation, which is 2.33 times that of the unmodified M-TiO 2 . This should be attributed to the suitable WO 3 doping and WO 3 modification.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Guanyu Liu,Huiyun Xia,Yanhui Niu,Xu Zhao,Gengtong Zhang,Lifang Song,Huaxin Chen
Practical significance in terms of the long-term effective application of photocatalytic coatings is greatly challenged by its easy pollution and poor self-cleaning performance. In this paper, a self-cleaning photocatalytic WO 3 -TiO 2 nanorod (MWT) /PDMS building coating (MWT coating) was prepared by spraying methods. The surface hierarchical structure fabricated by MWT and PDMS was a crux to construct a superhydrophobic surface, which endowed MWT coating with self-cleaning performance. Besides, the MWT coating exhibited prominent durability and antifouling property after 450 d practical application of the external wall. The excellent self-cleaning property of the coating was confirmed by the removal and resistance to the adhesion of powder particles. Meanwhile, the photocatalytic properties of MWT endowed MWT coating with the ability to degrade organic pollutants on the surface. The color difference of the coating polluted by methyl red was only 1.18 and 4.77 after 24 h UV and visible irradiation, respectively. This mutual benefit effect of self-cleaning and photocatalysis was also reflected in the degradation of NO. In the first five cycles, the degradation efficiency of NO decreased by 4.74% gradually under visible light due to the adhesion of oxidation products, and most of the MWT on the coating surface was regenerated after flushing, the PCD efficiency increased by 3.71%. Furthermore, after 30 days of outdoor weathering test, the PCD efficiency of MWT coating decreased by 11.74% and 12.05% under UV and visible light, respectively, which lays a foundation for the long-term effectiveness of the MWT coating in the process of use.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2014
·
IF 2.538
Liuyang Yang,Zhichun Si,Duan Weng,Youwei Yao
Porous WO 3 /TiO 2 hollow microspheres were prepared by a spray drying method for photodegradation of methylene blue and phenol . The catalysts were characterized by X-ray diffraction, Field Emission Scanning Electron Microscope , High Resolution Transmission Electron Microscope , N 2 adsorption–desorption measurements, Raman spectrometer, UV–Vis Diffuse Reflectance Spectroscopy and Zeta-Meter measurements. The results showed that the tungsten oxides mainly existed in highly dispersed amorphous form on anatase when the loading amount of tungsten oxide was below 3 mol%. The improved photocatalytic activity under UV light irradiation of the WO 3 /TiO 2 catalyst mainly arises from the enhanced charge separation efficiency rather than the improved light absorbance by highly dispersed amorphous tungsten oxides. Highly dispersed amorphous WO x can form a shallowly trapped site due to its similar band structure with TiO 2 . The strongly electron-withdrawing of tungsten oxide in highly dispersed state facilitates the electron transition between titanium and WO x , and consequently improves the charge separation. The enhanced acidity of catalyst by WO x in reactant environment also improved the charge separation efficiency due to the timely transition of holes and electrons accumulated on TiO 2 and WO x , respectively. However, the improved photocatalytic activity under visible light irradiation of the WO 3 /TiO 2 catalyst mainly arises from light harvest. TiO 2 containing 3 mol% WO 3 displayed the highest photocatalytic activity under UV light irradiation while that containing 4 mol% WO 3 present highest activity under visible light irradiation.
研究领域:
材料科学
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光催化
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环境化学
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纳米材料
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无机合成
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）