JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2016
·Vol. 91
·期 11
·2842-2851
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IF 2.738
Dingsheng Chen,Chaoping Cen,Jinxi Feng,Chunyang Yao,Waiqing Li,Shuanghong Tian,Ya Xiong
BACKGROUND It is of great interest to use pillared clay (PILC) as a cheap support for a selective catalytic reduction (SCR) catalyst. Al-Cr pillared clay (AlCr-PILC) has high thermal stability due to the introduction of polycations of Al. As a support, AlCr-PILC may show a co-catalytic effect in SCR processes because chromium oxide itself is an active SCR catalyst. The aim of this work is to investigate the potential of AlCr-PILC as a new low temperature SCR catalyst support. RESULTS A series of AlCr-PILC with Al:Cr molar ratio varying from 0:4 to 4:0 were successfully synthesized to support manganese and cerium active phase. MnCe/AlCr(2:2)-PILC exhibited the highest NO x conversion close to 100% at 200–300 °C, and more than 90% N 2 selectively over a wide temperature window of 140–300 °C. The catalytic activity of MnCe/AlCr-PILC in terms of both NO x conversion and N 2 selectivity is much higher than those of MnCe/Al-PILC, MnCe/Cr-PILC, AlCr-PILC, and the simple mixed MnCeAlCr, indicating the co-catalytic effect of AlCr-PILC support. CONCLUSION AlCr-PILC is a very promising low-temperature SCR catalyst support. The XRD, XPS, and H 2 -TPR measurements prove that the co-catalytic effect of AlCr-PILC occurred via the strong interaction between MnCe and the AlCr-PILC support. © 2016 Society of Chemical Industry
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
Reaction Chemistry & Engineering
·
2022
·Vol. 7
·期 10
·2121-2131
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IF 5.2
Yue Ma,Zhimin Shao,Xiaodong Wu,Yang Gao,Baofang Jin,Rui Ran,Zhichun Si,Zhenguo Li,Duan Weng
Urea is applied as an ammonia source for SCR in diesel vehicles, but incomplete urea decomposition may lead to insufficiency of NH3 and deposition of solid by-products. To improve the urea decomposition activity of Cu-SSZ-13 SCR catalysts, Cu-SSZ-13 was combined with TiO2 nanoparticles by a simple impregnation method. TiO2/Cu-SSZ-13 composites exhibited lowered decomposition temperatures of urea and related solid by-products. Thus, the composited catalysts showed higher NOx conversion and a lower amount of urea-related deposits than unmodified Cu-SSZ-13 in a simulated urea deposition scenario. The superiority of the urea decomposition activity of the composited catalysts was maintained upon 800 °C hydrothermal aging due to stabilized anatase over the catalysts according to XRD and Raman spectroscopy. H2-TPR, UV-vis, and STEM revealed the formation of Cu–Ti–O species due to Cu–Ti interactions, which was adverse to SCR activity, but no extra hydrothermal aging effect was observed on the composited catalysts compared with unmodified Cu-SSZ-13. This work showed the potential to improve the low-temperature urea-SCR performance of Cu-SSZ-13 via TiO2 modification.
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
DOI
高影响因子
CATALYSIS TODAY
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2019
·
IF 4.888
Shuohan Yu,Yiyang Lu,Fei Gao,Lin Dong
In this work, TiO 2 nano-octahedron and nano-rods were successfully synthesized, and Cu oxides were loaded on them. Structures of CuO/TiO 2 catalysts were studied by XRD, TEM, and Raman techniques. It was founded that TiO 2 nano-octahedron and nano-rods dominantly exposed (101) and (100) facets of TiO 2 , respectively. Cu cations located in tetrahedral vacant sites on (101) facet of TiO 2 and coordinated with 4 neighbor oxygen, whereas it located in octahedral vacant sites on (100) facet of TiO 2 and coordinated with 6 neighbor oxygen, which resulted in redox cycle Cu 2+ +Ti 3+ ⟵→Cu + +Ti 4+ and more acid sites on surface of CuO/TiO 2 nano-octahedron, and thus the enhanced NH 3 -SCR performance.
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Tingman Zhao,Bo Feng,Jiada Du,Shengdao Shan,Yun Shi
Low-temperature NH 3 -SCR of NO x technology was recognized as a promising way to control NO x emissions from industrial kilns at low temperatures. Except for SO 2 and H 2 O, lots of CO 2 exist in the flue gas of industrial kilns. However, there are few researches on the effects of CO 2 on the low-temperature NH 3 -SCR activity. To investigate the effects of CO 2 on the low-temperature NH 3 -SCR performance and mechanism of CeO x -biochar catalyst, a series of experiments employed. The results showed that the presence of CO 2 had an obvious inhibitory effect on the NH 3 -SCR performance of CeO x -biochar 0.6 at 150 °C. There was competitive adsorption between CO 2 and NO on the surface of CeO x -biochar 0.6 . CO 2 was mainly adsorbed on CeO 2 , which hindered the oxidation of NO and the adsorption of NO x on the catalyst surface. Meanwhile, although the presence of CO 2 could improve NH 3 adsorption capacity of CeO x -biochar 0.6 due to the formation of NH 4 HCO 3 and (NH 4 ) 2 CO 3 , the existence of carbonates and bicarbonates blocked the formation of active intermediates NH 4 NO 2 and NH 2 NO for NH 3 -SCR reaction. As a result, the NO x conversion of CeO x -biochar 0.6 was dropped from 96.9% to 40.8% at 200 °C. In view of the bicarbonate and carbonate species was unstable at high temperatures, the inhibitory effect of CO 2 on NH 3 -SCR reaction was gradually weakened with the increase of reaction temperature. The NH 3 -SCR activity of CeO x -biochar 0.6 was seldom affected by CO 2 at 300 °C. Finally, a CO 2 poisoning mechanism for NO x removal by NH 3 -SCR at low temperature was proposed.
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2021
·Vol. 11
·期 3
·314
·
IF 4.146
Lusha Zhou,Jinkun Guan,Chenglong Yu,Bichun Huang
The ethanol dispersion method was employed to synthesize a series of MnOx/SAPO-34 catalysts using SAPO-34 with the hierarchical pore structure as the zeolite carrier, which were prepared by facile acid treatment with citric acid. Physicochemical properties of catalysts were characterized by XRD, XPS, BET, TEM, NH3-TPD, SEM, FT-IR, Py-IR, H2-TRP and TG/DTG. NH3-SCR performances of the hierarchical MnOx/SAPO-34 catalysts were evaluated at low temperatures. Results show that citric acid etching solution at a concentration of 0.1 mol/L yielded a hierarchical MnOx/SAPO-34-0.1 catalyst withca.15 wt.% Mn loading, exhibiting optimal catalytic activity and SO2tolerance at low temperatures. Almost 100% NO conversion and over 90% N2selectivity at 120 °C under a gas hourly space velocity (GHSV) of 40,000 h−1could be obtained over this sample. Furthermore, the NO conversion was still higher than 65% when 100 ppm SO2was introduced to the reaction gas for 4 h. These could be primarily attributed to the large specific surface area, high surface acidity concentration and abundant chemisorbed oxygen species provided by the hierarchical pore structure, which could also increase the mass transfer of the reaction gas. This finding suggests that the NH3-SCR activity and SO2poisoning tolerance of hierarchical MnOx/SAPO-34 catalysts at low temperatures can be improved by controlling the morphology of the catalysts, which might supply a rational strategy for the design and synthesis of Mn-based SCR catalysts.
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
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2016
·
IF 2.208
Jixing Liu,Fuhong Yu,Jian Liu,Lifeng Cui,Zhen Zhao,Yuechang Wei,Qianyao Sun
A series of meso-microporous Cu-SAPO-34 catalysts were successfully synthesized by a one-pot hydrothermal crystallization method, and these catalysts exhibited excellent NH 3 -SCR performance at low temperature. Their structure and physic chemical properties were characterized by means of X-ray diffraction patterns (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), N 2 sorption-desorption, nuclear magnetic resonance (NMR), Inductively Coupled Plasma-Atomic Emission spectrometer (ICP-AES), X-ray absorption spectroscopy (XPS), Temperature-programmed desorption of ammonia (NH 3 -TPD), Ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS) and Temperature programmed reduction (TPR). The analysis results indicate that the high activities of Cu-SAPO-34 catalysts could be attributed to the enhancement of redox property, the formation of mesopores and the more acid sites. Furthermore, the kinetic results verify that the formation of mesopores remarkably reduces diffusion resistance and then improves the accessibility of reactants to catalytically active sites. The 1.0-Cu-SAPO-34 catalyst exhibited the high NO conversion (> 90%) among the wide activity temperature window in the range of 150–425°C.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Yanping Yang,Shengchen Li,Shunli Shi,Jie Hu,Zexi Xuchen,Shunmin Ding,Dan zhao,Shengjun Deng,Weiming Xiao,Shuhua Wang,Chao Chen
Manganese oxide (MnO x ) catalysts are promising for low-temperature NH 3 -Selective Catalytic Reduction (NH 3 -SCR) with their superior catalytic performance. However, the presence of alkali metals in flue gases, particularly potassium (K), leads to catalyst deactivation and limits their industrial application. This study investigates the synergistic effects of Ce and Nb doping on the K resistance and low-temperature NH 3 -SCR activity of MnO x . The surface acidity and redox properties of MnO x were modulated by Ce and Nb modification. In addition, the phase structure, surface state and active sites of the catalysts were characterized before and after K poisoning. The results indicated that Nb 0.05 Ce 0.05 MnO x exhibited exceptional low-temperature performance, achieving over 90 % NO conversion at 125-250°C, along with significant resistance to K poisoning·NH 3 -TPD and in-situ experiments revealed that the loss of acid sites is the primary cause of K poisoning. The mechanism follows the L-H mechanism with L-acid sites as the main active sites on the catalyst surface and bridging nitrate as the key intermediate state. This research provides valuable insights into enhancing the industrial applicability of MnO x- based catalysts for low-temperature denitrification.
研究领域:
催化化学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
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2024
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IF 5.7
Yong Shi,Xin Lan Ma,Jin Suo Gao,Feng Yun Yu,Chun Yan Li,Wei Xiong,Li Ping Huang
The catalytic activity, adsorption and synergistic effect over bimetallic MOF derivatives with different dopant metal were systemically compared. A series of Me-Cu/TiO 2 (Me=Fe, Co, Ni) derived from bimetallic Me/Cu-BTC MOFs were fabricated via a sacrificing template method and applied for CO-SCR. Among the bimetallic catalysts, Fe-Cu/TiO 2 presented the best low-temperature of nearly 100% NO conversion from 150 °C to 350 °C with good NO selectivity. For Me-Cu/TiO 2 (Me=Fe, Co, Ni), the productions of crucial Cu + intermediate were determined to be 51.17%, 50.45%,49.4% by XPS, which were consistent with their catalytic activity results. The superior redox behavior of Fe-Cu/TiO 2 can be attributed to its higher Oβ / (Oα +Oβ) ratio of 32.90% and the higher Me 2+ / Me 3+ ratio of 1.79. In situ infrared analysis revealed that the Fe doping not only improved the formation and stability of nitrate species, but also enhanced the quantity of Lewis acid sites by forming Cu + -CO. Furthermore, a possible low-temperature Langmuir-Hinshelwood (L-H) mechanism over Me-Cu /TiO 2 (Me=Fe, Co, Ni) was proposed.
研究领域:
材料科学
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环境催化
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
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2022
·
IF 13.7
Yongjun Ji,Shaomian Liu,Shaojia Song,Wenqing Xu,Liang Li,Yu Zhang,Wenxing Chen,Huifang Li,Jingang Jiang,Tingyu Zhu,Zhenxing Li,Ziyi Zhong,Dingsheng Wang,Guangwen Xu,Fabing Su
Pt-based catalysts are promising for the selective catalytic reduction of NOx by CO (CO-SCR), but some technical issues hinder their practical application, including the high Pt loading needed, high reduction temperature, and the low tolerance toward SO2. Here, we report a novel Pt catalyst for CO-SCR, which has negatively charged single-atom Pt embedded on CuO squares, and the latter is supported on CoAlO nanosheets. This Pt–CuO/CoAlO catalyst with an ultra-low Pt loading (0.02 wt %) exhibited 91% NO conversion and 80% N2 selectivity in 3% O2 at 200 °C. More importantly, it showed almost no activity loss in 200 ppm SO2 over a 15 h test. The theoretical calculations reveal that the negatively charged Pt has a stronger NO adsorption ability than the positively charged Pt, and Cu serves as the CO adsorption site. The much-weakened SO2 adsorption on Pt–CuO/CoAlO relative to the NO and CO adsorption effectively avoids the catalyst poisoning by SO2.
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
CHEMICAL ENGINEERING JOURNAL
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2022
·
IF 16.744
Wen Luo,Jing Rong,Wanxia Zhao,Keke Kang,Lulu Long,Xiaojiang Yao
CeO 2 –TiO 2 catalysts with four different morphologies were successfully synthesized by a hydrothermal method and tested for selective catalytic reduction of NO x with NH 3 (NH 3 –SCR). For the four catalysts, CeO 2 –TiO 2 nanocubes (CT–NC) and nanorods (CT–NR) preferentially exposed {1 0 0} and {1 1 0} facets, respectively; furthermore, nanosheets (CT–NS) and nanospheres (CT–NH) mainly exposed {1 1 1} facet. Interestingly, CT–NH catalyst showed the best NH 3 –SCR performance and the NO x conversion exceeded 97% at 325 °C. Through a series of characteristic methods manifested that the short–range ordered structure of Ce–O–Ti in CT–NH catalyst provided stronger surface acidic sites to promote the high–temperature activity. Moreover, the abundant Ce 3+ species and appropriate reduction ability on {1 1 1} facet of CT–NH catalyst also caused outstanding de NO x activity. Reaction mechanism study showed that the Langmuir–Hinshelwood (L–H) mechanism and Eley–Rideal (E–R) mechanism existed simultaneously on all catalysts in NH 3 –SCR reaction. Meaningfully, two types of E–R mechanism were present on CT–NH catalyst, while L–H mechanism was dominant.
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
Molecular Catalysis
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2018
·
IF 0
Sher Ali,Yushi Li,Tianrui Zhang,Syed ul Hasnain Bakhtiar,Xuesong Leng,Zhibin Li,Fulong Yuan,Xiaoyu Niu,Yujun Zhu
Citric acid method was employed to prepare a series of Nb-promoted Fe x -Nb 0 . 5- x -Ce 0.5 ( x = 0.45, 0.4, 0.35) oxides for selective catalytic reduction with NH 3 (NH 3 -SCR) of NO process. The structure, redox ability and reactivity of NH 3 and absorbed NO species on the catalysts were explored by using various characterization techniques such as X-ray diffraction (XRD), temperature program reduction with H 2 (H 2 -TPR), temperature program desorption of NH 3 (NH 3 -TPD), temperature program desorption of NO (NO-TPD), X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). It was found that the Nb promoted Fe x -Nb 0 . 5- x -Ce 0.5 ( x = 0.45, 0.4, 0.35) oxides catalysts showed outstanding NH 3 -SCR of NO activity, excellent N 2 selectivity and remarkable SO 2 /H 2 O resistance, meanwhile, Fe 0.4 -Nb 0.1 -Ce 0.5 exhibited above 90% NO conversion in the range of 180–400 °C, together with near 100% N 2 selectivity. The characterization results point out that the excellent catalytic performance of Fe 0.4 -Nb 0.1 -Ce 0.5 can be ascribed to the strong interaction among Nb, Fe and Ce oxides. The strong interaction not only increases the BET surface area and redox ability of the catalyst, but also significantly improves the acid amount leading to the enhancement of the adsorption and activation of NH 3 , which is advantage of the reactivity of adsorbed nitrate together with the adsorbed NH 3 species.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
APPLIED CATALYSIS A-GENERAL
·
2017
·
IF 4.339
Baohuai Zhao,Rui Ran,Xingguo Guo,Li Cao,Tengfei Xu,Ze Chen,Xiaodong Wu,Zhichun Si,Duan Weng
Mn/Ce/Ti and Mn/Ce/Nb/Ti catalysts were synthesized using a precipitation method and their catalytic activities for NO selective reduction with NH 3 at low temperatures were evaluated. Nb doping not only improved the activity of the catalyst over a wide temperature range but also restricted the generation of NO 2 and N 2 O. The Mn/Ce/Nb/Ti catalyst displayed 100% NO conversion from 150 to 250 °C and >90% N 2 selectivity below 250 °C. The specific surface area of the catalyst was increased and its surface acidity was strengthened after Nb doping. Moreover, Nb doping increased the NO oxidation ability and lowered the NH 3 oxidation activity of the catalyst. All the above factors contributed to enhancing the overall NH 3 -SCR performance of the Mn/Ce/Nb/Ti catalyst compared with that of the Mn/Ce/Ti one. The long-term stability and resistance to H 2 O and SO 2 of the Mn/Ce/Nb/Ti catalyst were also evaluated.
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）