PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2022
·
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
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Wuyuan Liu,Zihan Gao,Xiangyun Zhao,Jiajian Gao,Runnong Yang,Lin Yu
The Cr-doped CeO2–TiO2 catalysts (CrCeTi) were produced via a coprecipitation method and used for selective catalytic reduction (SCR). The CrCeTi catalyst has good catalytic performance and sulfur resistance. The results of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-TPD, NO-TPD, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR) suggested that the CrCeTi catalyst with high specific surface area (SSA), strong surface acidity, enhanced redox properties, and effective electron transfer (3Ce4+ + Cr3+ ↔ 3Ce3+ + Cr6+) were the important promotion factors for excellent SCR properties. The in situ diffuse reflectance infrared spectroscopy (DRIFTS) indicated that the incorporation of Cr could improve the adsorption capacity of nitrate and the activation capacity of NH3, which were conducive to enhancing the catalytic activity. The thermogravimetric analysis-mass spectrometry (TG-MS) confirmed that the doping of Cr reduced SO2 surface adsorption and promoted the decomposition of NH4HSO4 (ABS). Therefore, the CrCeTi catalyst showed excellent resistance to SO2 poisoning.
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 Materials Chemistry A
·
2018
·Vol. 6
·期 18
·8705-8711
·
IF 9.931
Hao Xu,Qinming Wu,Yueying Chu,Jingang Jiang,Ling Zhang,Shuxiang Pan,Changsheng Zhang,Longfeng Zhu,Feng Deng,Xiangju Meng,Stefan Maurer,Robert McGuire,Andrei-Nicolae Parvulescu,Ulrich Müller,Feng-Shou Xiao
2,6-methyl-N-methylpyridinium, as a novel organic template, is employed for the synthesis of RTH aluminosilicate zeolite with a SiO2/Al2O3 ratio of 17.6. The amount of 2,6-methyl-N-methylpyridinium template, the Na2O/SiO2 ratio, the SiO2/Al2O3 ratio, and the H2O/SiO2 ratio in the starting gel significantly influence the crystallization of RTH zeolite. Several analytical methods such as XRD, SEM, N2 sorption, TG-DTA, DRIFT and NMR were employed for the characterisation of the obtained RTH zeolites and to understand the crystallization process with the new template. Very interestingly, the crystallization of RTH zeolite with the new template takes a very short time (12 h at 130 °C and 50 min at 240 °C) compared with conventional RTH zeolite synthesis reported in the literature (72 h at 130 °C). Theoretical calculations show that this novel organic template has lower interaction energies for zeolite cage space filling than those of the organic templates previously reported in the literature, which lead to stronger structural directing. Kinetic results show that the activation energy of this novel organic template is much lower than that of the traditional one. Catalytic tests show that copper exchanged RTH zeolite (Cu-RTH) exhibits good catalytic properties in the NH3-SCR reaction and the H-RTH zeolite catalyst has excellent selectivities for ethylene and propylene in MTO reactions.
研究领域:
催化材料
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化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2022
·
IF 6.47
Longyi Xue,Ninghan Wei,Cheng Zhao,Xiaomei Hu,Junge Yun,Zimo Chen,Zhiyi Deng,Zhihang Chen
CeO 2 as selective catalytic reduction (SCR) catalyst has attracted wide attention due to its abundant surface acidity and excellent oxygen storage/release capacity. However, its further implication was hindered owing to insufficient catalytic activity and SO 2 resistance. Novel Cr doped CeO x catalysts were synthesized by solid phase method and used for NH 3 -SCR of NO x at middle-low temperature. The effect of Cr addition on the SCR performance and physicochemical properties of CeO 2 catalyst was investigated by activity test and characterizations. Among the tested catalysts, Cr(0.4)-CeO x catalyst exhibited excellent NO x removal efficiency, with >90% NO conversion within 180–300 °C, 100% NO conversion at 220 °C and outstanding SO 2 resistance at 240 °C under 100 or 600 ppm SO 2 . The characterizations results revealed that Cr modified CrCeO x catalyst could effectively increase BET surface area, pore volume, surface acidity and redox capacity. In situ DRIFTS indicated that SCR reactions over Cr(0.4)-CeO x catalyst followed Eley-Rideal mechanism and active –NH 2 was the major intermediate species. After sulfuration, Cr(0.4)-CeO x still exhibited excellent SCR activity due to the increase of Cr 6+ , Ce 3+ and O α concentration and the formation of Cr–O–Ce bond, new Brønsted acid site and more crystallized Cr 2 O 3 .
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2021
·Vol. 151
·期 8
·2250-2256
·
IF 3.186
Liu Qi,Wang Shihao,Xu Gang,Wu Minghong,Chen Jianjun,Li Junhua
Abstract A novel TiO 2 -supported vanadium-substituted tungstophosphoric acid (PW 11 V/TiO 2 ) catalyst was designed and applied for selective catalytic reduction of NO x by NH 3 . Compared with the commercial tungstophosphoric acid (PW 12 /TiO 2 ), PW 11 V/TiO 2 displayed a nearly 90% activity improvement at 300 °C. In addition, the favorable resistance and stability to SO 2 were also obtained over PW 11 V/TiO 2 catalyst. Phase analysis and spectroscopy results indicated the vanadium was successfully incorporated into the molecular structure of PW 12 , and the Keggin framework still keep stable over the TiO 2 support. H 2 -TPR test proved the incorporation of vanadium promoted the redox ability of PW 11 V. The present study provides us an effective way to improve the performance of catalytic removal of NO x through tungstophosphoric acid catalyst. Graphic Abstract
After introduction of V species, the obtained PW 11 V/TiO 2 catalyst show better NH 3 -SCR performance and N 2 selectivity than PW 12 /TiO 2 catalyst.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2023
·Vol. 13
·期 10
·3147-3157
·
IF 5
Hange Wang,Wen Chen,Wei Jin,Yueli Liu
SCR technology is considered to be the most effective method for denitrification. However, the low NOx conversion rate of the current catalysts at low temperatures limits their further application. Herein, Sn-doped modified CoAl-LDH carriers are synthesized by a hydrothermal method, and the typical hexagonal sheet structure of the MnOx(0.25)/CoSn3Al-LDO catalyst achieves 100% NO conversion at a wide range of 120–330 °C with a GHSV of 30 000 h−1, and the 100% NO conversion may be maintained at 200 °C for 30 h. After the introduction of 150 ppm SO2 at 200 °C, the NO conversion of the MnOx(0.25)/CoSn3Al-LDO catalyst is maintained at 73.4%, which is greatly improved compared with those of CoAl-LDO and MnOx(0.25)/CoAL-LDO catalysts (64.8% and 38.6%, respectively). The active components such as MnOx and Co3O4 are highly dispersed in the MnOx(0.25)/CoSn3Al-LDO catalyst. Sn doping increases the ratios of Mn4+/Mn3+ and Co3+/Co2+ as well as the adsorbed oxygen amount on the catalyst surface, and improves the redox capacity of the catalyst and increases the number of acid sites, resulting in the excellent low-temperature NH3-SCR performance of MnOx(0.25)/CoSn3Al-LDO.
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
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2021
·
IF 9.028
Guangzhi He,Meng Gao,Yue Peng,Yunbo Yu,Wenpo Shan,Hong He
Mn-based oxides exhibit outstanding low-temperature activity for the selective catalytic reduction of NOx with NH3 (NH3-SCR) compared with other catalysts. However, the underlying principle responsible for the excellent low-temperature activity is not yet clear. Here, the atomic-level mechanism and activity-limiting factor in the NH3-SCR process over Mn-, Fe-, and Ce-based oxide catalysts are elucidated by a combination of first-principles calculations and experimental measurements. We found that the superior oxidative dehydrogenation performance toward NH3 of Mn-based catalysts reduces the energy barriers for the activation of NH3 and the formation of the key intermediate NH2NO, which is the rate-determining step in NH3-SCR over these oxide catalysts. The findings of this study advance the understanding of the working principle of Mn-based SCR catalysts and provide a fundamental basis for the development of future generation SCR catalysts with excellent low-temperature activity.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Xuesong Liu,Peng Jiang,Yong Chen,Yaoguang Wang,Qiaoling Ding,Zhiming Sui,Hongfeng Chen,Zhongyun Shen,Xiaodong Wu
Two Ce-W-Ti mixed oxide catalysts were prepared by wet impregnation (CeW/Ti-I) and mechanical mixing (Ce/W/Ti-M) methods. CeW/Ti-I catalyst exhibits over 80% NO x conversion and nearly 100% N 2 selectivity at 200–550 °C. The superior catalytic performance is associated with the high dispersion of active CeO 2 and acidic WO 3 on TiO 2 and the synergistic effects among different components. The X-ray Diffraction, Raman spectroscopy, Nitrogen physisorption, X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction, temperature-programmed desorption of ammonia and infrared spectroscopy were performed. It is found that the formation of solid solutions, as well as the high specific surface area, would increase the amounts of Ce 3+ , oxygen vacancies and acid sites in the catalyst. These broaden the operating temperature window of NH 3 -SCR reaction and enhance the N 2 selectivity by facilitating “fast SCR” reaction at low temperatures and inhibiting the unselective oxidation of NH 3 at high temperatures.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Xinyu Li,Huawang Zhao,Yating Huang,Xiaomin Wu,Zhiwei Huang,Huazhen Shen,Guohua Jing
A composite catalyst was prepared by mechanically mixing Cu-SSZ-13 and MnCeTiO x to improve selective catalytic reduction (SCR) of NO x by ammonia. The optimal mass ratio of Cu-SSZ-13 and MnCeTiO x components in the composite catalysts was 1:1, where the NO x conversion was improved by around 40% in the temperature range of 150–300 °C compared with Cu-SSZ-13 alone. MnCeTiO x presented significantly stronger ability on the activation of NO to nitrates species than Cu-SSZ-13. Infrared (IR) and density functional theory (DFT) results showed that active nitrates intermediate on MnCeTiO x might migrate to Cu-SSZ-13, which assisted the oxidation of single Cu + to Cu 2+ to complete the Cu redox cycle. This avoided the rate-determining step that formation and oxidation of Cu + dimers in low-temperature SCR over Cu-SSZ-13. The research results are beneficial to the rational design of SCR catalysts with high-performance at low temperatures.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
Engineering
·
2025
·
IF 11.6
Ying Zhu,Jingjing Liu,Guangzhi He,Shaohua Xie,Wenpo Shan,Zhihua Lian,Fudong Liu,Hong He
Catalytic activity and hydrothermal stability are both crucial for the application of the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR catalyst) in diesel vehicles. In this study, a tin (Sn)-modified Ce–Nb mixed-oxide catalyst was synthesized as an NH 3 -SCR catalyst for NO x emission control. After the introduction of Sn, both the NH 3 -SCR activity and the hydrothermal stability of the catalyst were remarkably promoted. Even after hydrothermal aging at 1000 °C, the developed Ce 1 Sn 2 Nb 1 O x catalyst achieved more than 90% NO x conversion at 325–500 °C. Various methods, including N 2 -physisorption, X-ray diffraction, in-situ high-temperature X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption fine-structure spectroscopy, temperature-programmed reduction of hydrogen, temperature-programmed desorption of ammonia, and density functional theory calculations were used to investigate the promotional effects induced by the Sn species. The characterization results showed that the addition of Sn not only promoted the formation of the Ce–Nb active phase but also improved its thermal stability, contributing to the excellent NH 3 -SCR performance and hydrothermal stability. This study provides an excellent sintering-resistance catalyst for the application of diesel engine NO x emission control.
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
Catalysis Science & Technology
·
2022
·Vol. 12
·期 4
·1245-1256
·
IF 6.177
Jie Yang,Shan Ren,Mingming Wang,Zhichao Chen,Lin Chen,Lian Liu
Ce–Ti catalysts were considered as a promising replacement for V–Ti based catalysts for selective catalytic reduction (SCR) of nitrogen oxides (NO and NO2) with NH3. In this work, a CeO2/TiO2 catalyst was prepared by the impregnation method and studied by a series of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments. The results showed that CeO2 particles grew along TiO2 faces and amorphous cerium in the lattice of TiO2, both of which are present on the CeO2/TiO2 catalyst. NH4+ might adsorb on the Ti–O–Ce structures or TiO2–CeO2 interface as Brønsted acid sites, while two types of NH4+ species were distinguished by the time-resolved spectroscopic method due to the different increasing trends. Based on the temporal evolution transient in situ DRIFTS spectra, L-NH3 had higher activity than coordinated NH3 species, which suggested that gas phase NO reacted preferentially with L-NH3. The NH4NO3 intermediate dominated the SCR reactions over the CeO2/TiO2 catalyst, which followed the Eley–Rideal mechanism.
研究领域:
催化化学
·
环境科学
✓ 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）