JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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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
FUEL
·
2022
·
IF 8.035
Yangfan Chen,Hongyan Yan,Wenxin Teng,Jiangling Li,Weizao Liu,Shan Ren,Jian Yang,Qingcai Liu
NH 3 -SCR technology with commercialized V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalysts has become the most efficient technology for the removal of NO x from coal-fired power plants. However, the weaknesses of V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalysts such as the biotoxicity of vanadium species and high cost restrict their increased applicability. Fe 2 O 3 -based NH 3 -SCR catalysts show potential in placing traditional catalysts due to their good N 2 selectivity, excellent environmentally friendly performance, high thermal stability, and low cost. In this work, low cost Fe 2 O 3 -containing solid waste was exploited as the base material for NH 3 -SCR catalyst preparing. Moreover, bulk MoO 3 and MoO 3-x nanosheets decorated Fe 2 O 3 composite NH 3 -SCR catalysts were synthesized and both revealed conspicuously improved NO x removal efficiency compared with bare-Fe 2 O 3 catalyst. However, the N 2 selectivity of these two catalysts showed significant differences. Therefore, comprehensive characterizations, NH 3 oxidation experiments, and in-situ diffusion Fourier transform infrared spectroscopy (DRIFTS) experiments were performed to determine the N 2 O formation pathways of the above two catalysts. The redox properties were highly related to the N 2 O generated from NH 3 oxidation. Moreover, the huge difference in NH 3 and NO adsorption ability led to disparate reaction mechanisms over the two catalysts. This new understanding of the N 2 O formation mechanism has the potential to guide the rational design of improved NH 3 -SCR catalysts suffering from low N 2 selectivity.
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
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
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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
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
Catalysis Science & Technology
·
2023
·Vol. 13
·期 10
·3147-3157
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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
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催化化学
✓ 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
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Ruoyuan Li,Aixia Li,Junhua Li,Yao Wang,Zhiming Liu
Selective catalytic reduction of NO x by CO (CO-SCR) in the presence of O 2 is challenging because in this process CO is prone to being oxidized by O 2 , thus inhibiting NO x reduction by CO. Furthermore, SO 2 typically leads to the deactivation of the CO-SCR catalyst. Herein, a significant promoting effect of SO 2 on Ir/SiO 2 catalyst for the CO-SCR of NO x in the presence of O 2 is reported. In-situ X-ray Absorption Fine Structure (XAFS) and X-ray photoelectron spectroscopy (XPS) analysis showed that SO 2 does not affect the chemical nature of Ir 0 under reaction conditions. However, SO 2 can be oxidized to sulfate and deposit on the catalyst surface. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis demonstrated that the presence of SO 2 can inhibit the CO + O 2 reaction, thus leaving more CO available to reduce NO x over the active Ir 0 sites. As a result, the reduction of NO x is remarkably promoted even in the presence of O 2 and SO 2 .
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
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
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
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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
·
2023
·
IF 7.7
Liu Yang,Jing Li,Guoqiang Cao,Yiyan Yang,Wen Luo,Zhiqi Zhang,Lizhi Feng,Xinglai Zhang,Baodan Liu
This study reports on the development of highly-efficient Pt/CuO-Fe 2 O 3 /TiO 2 monolithic catalysts for the low-temperature conversion of NO to N 2 via CO-SCR. In this case, ultrathin TiO 2 nanosheet arrays are designed to in situ grow on flexible Ti mesh to provide more spaces/areas for the loading of highly-dispersed Fe 2 O 3 and CuO active components. Furthermore, Pt nanoparticles with an average size of 1.30 nm are effectively decorated on the surface of CuO-Fe 2 O 3 /TiO 2 . The H 2 -TPR and NO-TPD results demonstrate that the excellent synergistic effect between TiO 2 , CuO, Fe 2 O 3 and trace amounts of Pt is conducive to enhance the adsorption of NO and finally promote the CO-SCR. The obtained Pt/CuO-Fe 2 O 3 /TiO 2 catalysts exhibit excellent CO-SCR performance with 100 % NO conversion, and 100 % N 2 selectivity at 250 °C, showing great potential of de-NO x application by using toxic CO as reductant in industry.
研究领域:
环境科学
·
催化材料
✓ 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）