APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Juan Zhang,Yulong Shan,Ling Zhang,Jinpeng Du,Hong He,Shichao Han,Chi Lei,Sen Wang,Weibin Fan,Zhaochi Feng,Xiaolong Liu,Xiangju Meng,Feng-Shou Xiao
As a commerical catalyst of high silica CHA zeolite for NH 3 -SCR reaction, controllable Al sites in CHA framework for improving catalytic performance are rarely reported. In this work, two organic templates (TMAda + and DMCHA + ) were employed to prepare aluminosilicate CHA zeolite with similar Si/Al ratios, donated as CHA-T and CHA-D. Detailed characterizations demonstrate that two completely distinguishable crystallization pathways can be identified as the preferential formation of smaller D6R units for CHA-D with DMCHA + and larger 8MRs for CHA-T with TMAda + , resulting in spatially closer Al sites in CHA-D than CHA-T. As an interpretation, CHA-D with more paired Al atoms in 6MR generating more hydrothermally stable Cu 2+ -2Z sites contributes to higher activity than CHA-T at 400−550 °C. These results suggest that the crystallization pathways directed by rational choice of organic templates might be responsible for the controllable Al sites in the framework, which is important for designing efficient NH 3 -SCR catalysts.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Chemistry
·
2023
·
IF 7.3
Hari Bandi,Ashok Kumar Kakarla,Kedhareswara Sairam Pasupuleti,R. Shanthappa,P.P. Waifalkar,Moon-Deock Kim,Jae Su Yu
Vanadium-based metal oxides are used in different fields like gas sensors, supercapacitors , and lithium (Li)-ion batteries due to their availability, layered structure, and facile synthesis. Herein, we report a temperature-effective strategy to synthesize hexagonal-shaped zinc vanadate (Zn 2 VO 4 (ZVO)) nanostructures (NSs) via a facile hydrothermal method without any further doping of an element or carbon additive. The synthesized ZVO NSs provide large surface area, low energy band gap, and fast Li + diffusion. When compared with the ZVO-120 (synthesized at 120 °C) and ZVO-160 samples, the ZVO-140 sample shows a lower energy band gap value of 2.57 eV with higher surface area (37 m 2 g −1 ) and porous nature. As an anode material for Li-ion batteries, the ZVO-140 demonstrates superior rate capability (126 mA h g −1 at 1.5 A g −1 ) and excellent cycling performance (576 mA h g −1 after 100 cycles at 0.05 A g −1 and 327 mA h g −1 after 2000 cycles at 1 A g −1 ) as well as good Li + diffusion coefficient (2.61 × 10 −8 cm 2 s −1 ). Due to these synergistic benefits, ZVO NSs are used for NH 3 gas sensing application. The ZVO-140 sample exhibits excellent sensitivity (47.3%) at 190 °C with fast response/recovery time (136 s/128 s) and reliable stability towards NH 3 gas (100 ppm) at 190 °C, when compared with counterparts (ZVO-120 and ZVO-160). This preparation strategy may initiate the design of advanced ZVO-based materials for multifunctional applications.
研究领域:
材料科学
·
能源存储
·
传感器技术
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2015
·Vol. 5
·期 4
·2260-2269
·
IF 5.426
Qiulin Zhang,Xin Liu,Ping Ning,Zhongxian Song,Hao Li,Junjie Gu
Mesoporous Ce–Ti–MoOx catalysts have been prepared by stabilization with an in situ formed carbon template and used for selective catalytic reduction of NOx with NH3 (NH3-SCR). The Ce–Ti–MoOx catalysts were characterized by N2 adsorption–desorption, XRD, HR-TEM, H2-TPR and XPS analysis. It was found that the stabilization with a carbon template obviously improved the NOx conversion of the Ce–Ti–MoOx catalyst and the pore distribution. The Ce–Ti–MoOx catalyst stabilized with a carbon template at 850 °C in N2 exhibited the best NH3-SCR activity and showed a uniform mesopore distribution, and more than 90% NOx conversions were obtained at 175–425 °C with a GHSV of 60 000 h−1. The high stabilization temperature with a carbon template in N2 not only led to an increase in specific surface area, pore volume and low-temperature SCR activity, but also contributed to the enhanced redox properties, highly dispersed titanium or molybdenum species and narrow mesopore distribution. The treatment of Ce–Ti–MoOx with a high calcination temperature for removal of the carbon template led to a drastic decrease in surface area, an abrupt decrease in surface oxygen and cerium, production of rutile TiO2, and a correspondingly low SCR activity.
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
Journal of Physical Chemistry C
·
2021
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IF 4.126
Yanye Zhu,Fangyuan Zhou,Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
The NH3–SCR process could provide cobenefits for VOCs abatement from industrial sources. Ceria-based catalysts have received considerable attention for NOx removal at low-medium temperatures. In this study, the reaction behaviors of the simultaneous control of NOx and methanol over the Sb0.5CeZr2Ox catalyst were investigated. It was found that the presence of methanol reduced NOx conversion at low temperatures, while the methanol mineralization rate was promoted in the SCR reaction environment. This effect weakened as the temperature increased, and both NOx and methanol could be effectively removed (with efficiencies more than 90%) within 250–350 °C at a CH3OH/NO ratio of no more than 1:1. NO adsorption and oxidation were greatly suppressed by methanol, thereby inhibiting the SCR reaction via the Langmuir–Hinshelwood (L-H) mechanism. Meanwhile, the formation of formamide via NH3 and intermediates of methanol oxidation was also responsible for the deactivation effect on the SCR reaction at low temperatures. The presence of NO was found to be the main reason for enhanced methanol deep oxidation as NO can promote the rehealing process of active oxygen species.
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
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2021
·
IF 3.995
Li Huang,Yiqing Zeng,Yibo Gao,Hu Wang,Yuhao Zong,Zhengfeng Chang,Shule Zhang,Pei Han,Yang Yu
The oxidation of SO 2 into SO 3 promote the formation of NH 4 HSO 4 (ABS), which can cover surface active sites catalyst, and then leading to the decrease of NH 3 -SCR De-NO x activity. In this work, phosphorus species were loaded on the V 2 O 5 -MoO 3 /TiO 2 De-NO x catalyst to enhance its SO 2 resistance via inhibiting the SO 2 /SO 3 conversion. XRD and N 2 -adsorption results showed that phosphorus has little impact on the structure and pore property of the catalyst. The results of XPS , H 2 -TPR, and NH 3 -TPD analyses illustrated that suitable amount of phosphorus (1%) increases the content of polymeric vanadate and chemisorbed oxygen (O α ) of the catalyst, which is benefit to the SCR process. Phosphorus species decreases the SO 2 absorbability and SO 2 oxidation activity of V-Mo-P/Ti catalysts, thus it exhibits higher NH 3 -SCR activity than that of the P-free catalyst at presence of SO 2 due to the lower SO 2 /SO 3 conversion and fewer amount of NH 4 HSO 4 deposition.
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
SENSORS AND ACTUATORS B-CHEMICAL
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2020
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IF 7.1
Weiwei Meng,Lei Dai,Yuehua Li,Zhangxing He,Wei Meng,Huizhu Zhou,Ling Wang
Mixed potential NH 3 sensors with La 9.95 K 0.05 Si 5 AlO 26.45 (LKSAO) as the solid electrolyte and Bi 1-x Ag x VO 4- δ as the sensing electrode (SE) were developed. Bi 1-x Ag x VO 4- δ was produced by solid state reaction and then characterized by XRD, XPS, SEM and EDS. As revealed from the results, The BiVO 4 samples exhibit an unchanged crystalline structure after Ag doping molar amount x≤0.2, accompanied by the growth of the particle. The sensor based on Bi 1-x Ag x VO 4 - δ exhibit the noticeably enhanced sensing performance to NH 3 in contrast to the sensor using BiVO 4 , including its larger response potential (Δ V ) and higher sensitivity. For instance, the sensors based on BiVO 4 and Bi 0.8 Ag 0.2 VO 4 - δ at 400 °C exhibit the sensitivities of -28.1 and -77.3 mV/decade, respectively. Nevertheless, by Ag doping, there is no effective improvement of the anti-interference ability of the sensor against NO and NO 2 . To address the mentioned problem, CuO, NiO and La 0.8 Sr 0.2 MnO 3 (LSM) were used as reference electrodes (RE). As suggested from the results, using CuO and NiO as the reference electrodes can obviously reduce the cross-sensitivity of the sensor to NO and NO 2 , whereas the sensitivity slightly decrease.
研究领域:
材料科学
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传感技术
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2022
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IF 7.926
Wei Li,Xuesen Du,Zhi Li,Yaqin Tao,Jingyu Xue,Yanrong Chen,Zhongqing Yang,Jingyu Ran,Vladislav Rac,Vesna Rakić
Vanadia-based catalysts are widely used in selective catalytic reduction (SCR) reaction for reducing nitrogen oxides emissions, however, they only exhibit sufficient DeNO x efficiency within a narrow temperature window. In this study, a catalyst embedded with electrothermal alloy was prepared. The catalyst surface temperature could be heated using the electrothermal alloy, in order to widen the operating temperature window of the V 2 O 5 -WO 3 /TiO 2 catalyst. Experimental results revealed that the electrothermal alloy embedded V 2 O 5 -WO 3 /TiO 2 catalyst can maintain superior NH 3 -SCR performance and high resistance to H 2 O in a wide gas temperature range of 100–400 °C by controlling the surface temperature. In the meantime, the NH 4 HSO 4 poisoned catalyst could be efficiently regenerated through electric heating, and NO x conversion can be restored to the level of fresh samples. Additionally, the effect of additives including methylcellulose and glass fiber , on the physicochemical properties of the plate-type catalyst was also investigated, and the catalyst samples were characterized by means of BET, XRD , NH 3 -TPD, H 2 -TPR, TG and SEM-EDS. This study proves the electric heating strategy is a promising way to enhance the performance of the V 2 O 5 -WO 3 /TiO 2 during wide temperature SCR applications.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
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IF 10.7
Honghong Yi,Ruzhu Jia,Xiaolong Tang,Dongjuan Kang,Qingjun Yu,Fengyu Gao,Shunzheng Zhao,Yunpeng Liu
Electrocatalyst reduction of nitrogen oxides (NOx) in the industrial flue gas to synthesize NH3 can not only greatly improve the electrochemical efficiency of NH3 production, but also realize the emission reduction and resource utilization of air pollutants. Purposeful structural optimization of catalysts is a key research challenge in this field. Firstly, density functional theory (DFT) calculations found that the formation of surface oxygen vacancies could be promoted by constructing metal cation vacancies on the catalyst surface, which in turn optimized the NO adsorption configuration and improved the catalytic activity. By this guidance, CoAl layered double hydroxides (CoAl-LDH) nanosheets containing Al atomic vacancies were prepared by alkali etching. Experimental results show that a suitable alkali etching time with aqueous NaOH can significantly enhance the electrocatalytic activity of the CoAl-LDH nanosheets for NO reduction to NH3. Compared with pristine CoAl-LDH (0.097 mg cm-2 h-1), the NH3 yield rate reached 0.310 mg cm-2 h-1 at -1.1 V vs. the reversible hydrogen electrode after alkali etching for 4 h, which increased by 2.2 times. The catalyst characterization and theoretical calculation results indicate that the abundant frustrated Lewis pairs (FLPs) on the surface of catalysts containing cation vacancies are the origin of the enhanced activity.
研究领域:
材料科学
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环境科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2015
·
IF 3.368
Xiaole Weng,Xiaoxia Dai,Qingshan Zeng,Yue Liu,Zhongbiao Wu
Heteropoly acids (HPAs) have been effectively utilized in selective catalytic reduction (SCR) of NO to improve the NH 3 absorption capacity and alkaline/alkali metal resistance for SCR catalysts. However, despite the promise on super-acidities, their other properties that would work on SCR process are still lack of exploration. In this study, a 12-tungstaphosphoric acid (H 3 PW 12 O 40 , HPW) was selected to modify a well-reported CeO 2 catalyst. The resulted CeO 2 /HPW catalyst was subsequently utilized for SCR of NO with excess NH 3 , which revealed a significantly promoted performance in SCR reaction. DRIFT analyses showed that the unique NO 2 absorption capacity of HPW could prevent the NO 2 being further oxidized into nitrate species and the abundant Brønsted acid sites could effectively retain the NH 3 , avoiding them being over-oxidized at evaluated temperatures. The presence of NO 2 was demonstrated able to induce a so called “fast SCR” reaction over the CeO 2 /HPW catalyst, which effectively facilitated the SCR reaction. Furthermore, we have also constructed a CeO 2 @HPW catalyst, which showed an enhanced SO 2 poisoning resistance in SCR reaction.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 6
·期 14
·5543-5553
·
IF 5.287
Xin Zhao,Lei Huang,Supawadee Namuangruk,Hang Hu,Xiaonan Hu,Liyi Shi,Dengsong Zhang
A novel Zr–CeVO4/TiO2 catalyst was developed for the selective catalytic reduction (SCR) of NO with NH3. Both TiO2 nanosheets (TiO2-NS) and nanoparticles (TiO2-NP) with different crystal facets were used as supports for the catalyst. It was found that the TiO2-NS-supported catalyst showed much better activity, stability and H2O/SO2 durability than the TiO2-NP-supported catalyst. In particular, the catalyst loading amount was much lower than those of previously reported vanadate-based SCR catalysts. The crystal structures and morphologies were analysed by X-ray diffraction (XRD), Raman spectroscopy and (high-resolution) transmission electron microscopy ((HR)TEM). The redox properties, surface active species and acid sites of the catalysts were investigated through hydrogen temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), ammonia and nitrogen oxide temperature-programmed desorption (NH3-TPD and NOx-TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs) experiments. The improved activity at lower temperature was due to the presence of more active oxygen species and Brønsted acid sites, as well as the formation of NO2 on the surface of the TiO2 nanosheets which have exposed (001) facets. The enhanced stability and H2O/SO2 durability of Zr–CeVO4/TiO2-NS was due to the limited formation of NH4NO3 and (NH4)2SO4/NH4HSO4. The excellent low operation temperature, low vanadium content and absence of WO3(MoO3) in this catalyst indicated that it has promising potential as a SCR catalyst for practical 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
RSC Advances
·
2017
·Vol. 7
·期 51
·32146-32154
·
IF 3.108
Chengkai Pang,Yuqun Zhuo,Qiyu Weng
A series of Mn-exchanged SAPO-34 catalysts were synthesized and developed as catalysts for the low temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen. 4Mn/SAPO-34 showed the highest SCR activity in the temperature range of 120–210 °C. The microstructure of zeolite supports, acidity, manganese species and reaction mechanism were investigated in detail by BET, NH3-TPD, UV-Vis, H2-TPR, XPS and in situ DRIFTS. Mn3+ and Mn4+ related species were proved to be the active sites for the SCR reaction. The Eley–Rideal mechanism was proved to be effective on 4Mn/SAPO-34 for the low temperature SCR reaction in which coordinated NH4+ species react with gas-phase NO to form an activated transition state and subsequently decomposed to N2 and H2O.
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
FUEL
·
2022
·
IF 8.035
Yiqing Zeng,Weilong Rong,Shule Zhang,Yanan Wang,Qin Zhong
Ammonia selective catalytic reduction (NH 3 -SCR) technique for nitrogen oxide (NO x ) elimination of low temperature flue gas (<200 °C) requires huge energy consumption and operation costs. In this work, a CuO modified V 2 O 5 -WO 3 /TiO 2 (Cu/VWTi) catalyst are constructed to achieve the aim of enhancing the temperature of flue gas via using the heat released by CO oxidation, thereby promoting the NH 3 -SCR of NO x reaction. Benefiting from the synergistic effect between CuO and VWTi in the adsorption and activation of reactants, Cu/VWTi catalyst shows high NO x (>90%) and CO (>90%) removal efficiency at the temperature range of 225–270 °C and a GHSV of 40,000 h −1 . Moreover, it is found that the completely oxidation of 2000 ppm CO can increase the flue gas temperature by about 20 °C. Therefore, developing catalyst that can achieve simultaneously NH 3 -SCR of NO x and CO oxidation is a feasible method to deduce the energy consumption and operation costs of NH 3 -SCR of NO x system in low temperature flue gas. Finally, the reaction process and SO 2 deactivation effect over Cu/VWTi catalyst was studied via in-situ DRIFT. This work might provide some guidance for the design of catalysts to eliminate multiple pollutants.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）