JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2021
·
IF 6.064
Bichun Huang,Hansun Fang,Huajun Huang,Meijuan Lu,Chenglong Yu
A one-pot synthetic method was used to prepare copper (Cu)-modified manganese (Mn)-rich MnSAPO-34 catalysts, which were then used for NO x removal from stationary-source flue gas. The addition of Cu to these Mn-rich MnSAPO-34 catalysts significantly enhanced their low temperature (LT) selective catalytic reduction (SCR) activity and H 2 O resistance. The Mn 0.4 Cu 0.05 SAPO-34 catalysts demonstrated excellent LT NH 3 -SCR activity, with NO x removal being >90% from 160 to 300 °C. In addition, Mn 0.4 Cu 0.05 SAPO-34 catalysts exhibited high H 2 O resistance. This excellent performance was ascribed to strong synergistic effects between Mn 4+ and isolated Cu 2+ species in Mn 0.4 Cu 0.05 SAPO-34 catalysts, leading to suitable redox ability. The results of in situ FT-IR analysis indicated that LT-SCR reactions mainly proceeded by an Eley–Rideal reaction pathway at 200 °C in Cu-modified manganese-rich MnSAPO-34 catalysts. Thus, Mn 0.4 Cu 0.05 SAPO-34 was considered as a promising candidate for NO x removal from flue gas of stationary sources at low temperatures.
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
JOURNAL OF RARE EARTHS
·
2019
·
IF 2.846
Lei Chen,Ding Wang,Jiadao Wang,Duan Weng,Li Cao
The CeO 2 -TiO 2 (CeTi) and CeO 2 /WO 3 -TiO 2 (CeWTi) catalysts were prepared by sol-gel method. The as-prepared catalysts were hydrothermally treated at 760 °C for 48 h in air containing 10 vol% H 2 O to obtain the hydrothermal aged catalysts. The sulfur aged catalysts were treated at 400 °C with 100 ppm SO 2 , 10% water vapor, air balance for 48 h and catalysts. The powder X-ray diffraction (XRD) and Raman results indicate that the crystallization of hydrothermal aged catalysts is more serious than sulfur aged catalysts. In addition, tungsten species can stabilize the CeTi catalyst from grain growth. According to the results of in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS), temperature-programmed desorption of ammonia (NH 3 -TPD), H 2 temperature-programmed reduction (H 2 -TPR) and ammonia oxidation , the aging process leads to loss of surface area, redox properties, surface acidities and surface ceria concentration, especially for the hydrothermal aging. The NH 3 -NO/NO 2 SCR performances of sulfur aged catalysts are better than that of hydrothermal aged catalysts. Compared with CeTi catalyst, the addition of tungsten inhibits the crystallization of catalyst. So that more acid sites and active sites are retained. This is also the reason why tungsten addition improves the NH 3 -NO/NO 2 SCR performance of CeTi catalyst.
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 Science & Technology
·
2021
·Vol. 11
·期 15
·5125-5134
·
IF 6.119
Yanke Yu,Xianfang Yi,Jiali Zhang,Zhaojian Tong,Changwei Chen,Mudi Ma,Chi He,Jinxiu Wang,Jinsheng Chen,Bingbing Chen
Non-vanadium-based catalysts with high SO2 tolerance are still interesting in selective catalytic reduction of NO by NH3 (NH3-SCR) and SO2 adsorption is the foremost step for the deactivation of catalysts. In order to alleviate the adsorption of SO2, we fabricated a series of rhenium (Re; without stable sulfate) supported TiO2 catalysts and studied their SO2 tolerance for the first time. Owing to suitable surface acidity and reducibility, ReOx/TiO2 catalysts exhibited satisfactory activity in a wide temperature range of 250–350 °C. As expected, experimental results and DFT calculations indicated that SO2 adsorption on ReOx/TiO2 catalysts was rather weak, thus the catalysts performed excellent SO2 tolerance in the NH3-SCR reaction. Moreover, in situ DRIFTS indicated that the NH3-SCR reaction on ReOx/TiO2 catalysts followed the Eley–Rideal mechanism and SO2 had little effect on the reaction mechanism. Our findings should provide new insights into the development of SCR catalysts with high SO2 tolerance.
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
RESEARCH ON CHEMICAL INTERMEDIATES
·
2022
·Vol. 48
·期 7
·3007-3018
·
IF 3.134
Liu Fengyuan,Li Junqi,Chen Chaoyi,Ning Deyang,Yang Jian,Chu Zhiyao,Mao Xisong,Lan Yuanpei
A novel tactic was employed to evaluate the low-temperature NH 3 -SCR (selective catalytic reduction) NO x removal property of manganese oxides (MnO x ) in various valence states, avoiding the influences of size, morphology and synthetic method on catalytic activity. Firstly, similar sized hollow-spherical MnO 2 , Mn 2 O 3 , Mn 3 O 4 and MnO were obtained by decomposing MnCO 3 at 440 and 500 °C in Air, 430 °C in H 2 and Ar, respectively. The orders of MnO x catalytic activity varied at different reaction temperature range, while MnO 2 showed the best NO conversion. Surface acidity has significant influences on the SCR activity, Mn 3 O 4 exhibits a better catalytic property than Mn 2 O 3 below 300 °C, and conversely, Mn 2 O 3 has a better high-temperature NO conversation than Mn 3 O 4 due to a stronger NH 3 adsorption ability above 300 °C. MnO will be oxidized in the studied atmosphere with 5% O 2 to Mn 3 O 4 , Mn 5 O 8 and finally to Mn 2 O 3 successively, and the mixed phases of MnO/Mn 3 O 4 or Mn 3 O 4 /Mn 5 O 8 exhibit a better catalytic activity than Mn 2 O 3 at 200–300 °C.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Hanzi Liu,Jibin Yuan,Xinlin Xie,Junlin Peng,Lei Liu,Shilin Zhao,Zhiqiang Sun
In zeolite catalysis, the evolving composition of acid-relevant intermediates crucially influences the selective reduction of nitrogen oxides (NO x ). This process faces challenges, notably the undesired oxidation of NH 3 to NO x at high temperatures (>500 °C). Herein, we employ transient gas pulse spectroscopy to probe the behavior of NH 4 + species and related ligands in H- and Fe-exchanged zeolites. The synthesized HSSZ-13 exhibited an intrinsic de-NOx efficiency of 71.0 % and a N 2 selectivity of 99.4 % at 800 °C. A direct correlation between acid-related intermediate intensities and reaction rates was identified, varying with zeolite structure. In-situ spectroscopy and theoretical calculations revealed that the conjugation unit at the Brønsted site stabilizes the occupied π-orbital of NH 4 + , maintaining a moderate energy barrier for dehydrogenation and suppressing over-oxidation, thereby enhancing NH 3 adsorption and activation. These findings provide new implications for modulating NH 4 + intermediates and Fe-coordinated complexes within zeolites, enabling a more efficient redox cycle for high-temperature SCR applications.
研究领域:
催化化学
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环境化学
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材料科学
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物理化学
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工业催化
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Jianyi Lu,Zhiyong Zhou,Hanzhi Zhang,Zhe Yang
SO 3 generated in coal-fired boiler and selective catalytic reduction (SCR) process has become a significant problem due to its adverse effects on boiler facilities and air environment. The factors influenced conversion rate of SO 2 to SO 3 (SO 2 /SO 3 ) during SCR process were studied and evaluated, which included the effects of flue gas composition and SCR catalyst components on the conversion of SO 2 /SO 3 . SO 3 was trapped by the condensation and isopropanol absorption method, and SO 4 2− concentration was detected by spectrophotometer. The results showed that a certain concentration of NH 3 in the flue gas significantly promoted the conversion rate, but when NH 3 and NO coexisted, NO inhibited the catalytic action of NH 3 , while NO itself and O 2 had small effect on the conversion rate. Besides, the conversion rate of SO 2 increased with the increase of Ti and V content in the catalyst, and SiO 2 and BaO abated the catalytic oxidation of SO 2 , while WO 3 promoted the formation of SO 3 .
研究领域:
环境工程
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化学工程
·
能源技术
·
空气污染控制
✓ 已验证
DOI
高影响因子
HYDROMETALLURGY
·
2019
·
IF 3.465
Wenbo Lou,Yang Zhang,Shili Zheng,Ping Li,Ying Zhang,Yi Zhang,Bo Zhao,Zhefei Li,Wei Jin
China generates a large number of scrapped selective catalytic reduction (SCR) catalysts in the fossil fuel combustion plants every year. As a result, there is a giant quantity of 5 × 10 5 t scrapped V 2 O 5 -WO 3 /TiO 2 SCR catalyst annually worldwide, in which arsenic poisoning is a major cause of catalysts deactivation . In this study, a novel cleaner recovery process of alkaline-acid stepwise leaching was proposed for the high‑arsenic scrapped SCR catalysts to achieve excellent arsenic removal and structural reforming. It is found that arsenic can be completely removed from 1.92% to below the detection limit, and the surface area of regenerated catalysts is restored to 31 m 2 /g (similar to that of commercial catalysts). In the subsequent pickling and regeneration, Na + can be eliminated to obtain anatase-type TiO 2 for further activity recovery. Besides, valuable elements (W, V) have been successfully recycled by leaching the As-containing solid waste with ammonium salt. After replenishing active components, regenerated catalyst exhibits comparable activity with the commercial fresh catalyst, offering a promising method for scrapped catalyst recovery and further understanding of cleaner produces for waste management .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Zhipeng Yang,Siru Lu,Tianyu Wu,Hong Yao,Changan Zhou,Chao Wang,Kui Ma,Lei Song,Hairong Yue
Acid sites and redox sites with high thermal stability are crucial for the NH 3 -SCR catalyst for diesel vehicles. The surface acidity of FeTi catalysts is improved by modified with the solid acid of PO 4 3- or WO 3 . The acid-modified FeTi catalysts show superior NH 3 -SCR activity hydrothermal stability with a wide temperature window. The introduction of acid groups not only provides a large number of Brønsted acid sites but also promotes high dispersion of the active species of redox sites due to the formation of the structure P-O-Fe/W-O-Fe. The P-O-Fe/W-O-Fe structure can also improve the redox properties of the FeTi catalysts and inhibit the phase transformation of the TiO 2 support during high-temperature hydrothermal process. The reaction kinetics indicate that the reaction rate is primarily related to the concentration of NO. The mechanistic study indicates that the catalytic reaction is primarily governed by the Eley-Rideal mechanism.
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
Catalysts
·
2016
·Vol. 6
·期 8
·112
·
IF 2.964
Xiaobo Wang,Lei Zhang,Shiguo Wu,Weixin Zou,Shuohan Yu,Ye Shao,Lin Dong
A series of Fe–Ce–Ti catalysts were prepared via co-precipitation method to investigate the effect of doping Ce into Fe–Ti catalysts for selective catalytic reduction of NO with NH3. The NO conversion over Fe–Ce–Ti catalysts was considerably improved after Ce doping compared to that of Fe–Ti catalysts. The Fe(0.2)–Ce(0.4)–Ti catalysts exhibited superior catalytic activity to that of Fe(0.2)–Ti catalysts. The obtained catalysts were characterized by N2adsorption (BET), X-ray diffraction (XRD), temperature programmed reduction (H2-TPR), temperature programmed desorption (NH3-TPD), Fourier transform infrared (FT-IR) spectrophotometry, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The data showed that the introduction of Ce results in higher surface area and better dispersion of active components on the catalyst surface and enhances the amount of surface acid sites. The interactions between Fe and Ce species were found to improve the redox ability of the catalyst, which promotes catalytic performance at low temperature. The XPS results revealed that Fe3+/Fe2+and Ce4+/Ce3+coexisted on the catalyst surface and that Ti was in 4+ oxidation state on catalyst surface. Ce doping increased the atomic ratio of Fe/Ti and Ce/Ti and enhanced the surface adsorbed oxygen species. In addition, Fe(0.2)–Ce(0.4)–Ti catalyst also showed better tolerance to H2O and SO2and up to 92% NO conversion at 270 °C with 200 ppm SO2added over 25 h, which suggests that it is a promising industrial catalyst for mid-low temperature NH3–selective catalytic reduction (SCR) reaction.Keywords:SCR;denitration;catalytic activity;synergistic effect;SO2resistance
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Scientific Reports
·
2017
·
IF 4.259
Kunpeng Li,Rongzhen Zhang,Yan Xu,Zhimeng Wu,Jing Li,Xiaotian Zhou,Jiawei Jiang,Haiyan Liu,Rong Xiao
(S)-carbonyl reductase II (SCRII) from Candida parapsilosis is a short-chain alcohol dehydrogenase/reductase. It catalyses the conversion of 2-hydroxyacetophenone to (S)-1-phenyl-1,2-ethanediol with low efficiency. Sortase was reported as a molecular "stapler" for site-specific protein conjugation to strengthen or add protein functionality. Here, we describe Staphylococcus aureus sortase A-mediated crosslinking of SCRII to produce stable catalysts for efficient biotransformation. Via a native N-terminal glycine and an added GGGGSLPETGG peptide at C-terminus of SCRII, SCRII subunits were conjugated by sortase A to form crosslinked SCRII, mainly dimers and trimers. The crosslinked SCRII showed over 6-fold and 4-fold increases, respectively, in activity and k cat /K m values toward 2-hydroxyacetophenone compared with wild-type SCRII. Moreover, crosslinked SCRII was much more thermostable with its denaturation temperature (T m ) increased to 60 °C. Biotransformation result showed that crosslinked SCRII gave a product optical purity of 100% and a yield of >99.9% within 3 h, a 16-fold decrease in transformation duration with respect to Escherichia coli/pET-SCRII. Sortase A-catalysed ligation also obviously improved T m s and product yields of eight other short-chain alcohol dehydrogenases/reductases. This work demonstrates a generic technology to improve enzyme function and thermostability through sortase A-mediated crosslinking of oxidoreductases.
研究领域:
生物化学
·
酶工程
·
蛋白质工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yi Li,Yanping Li,Pengfei Wang,Wenping Hu,Suge Zhang,Qiang Shi,Sihui Zhan
A series of MnFeO x nanorods with different Fe/Mn molar ratios were successfully synthesized by the hydrothermal method for low temperature selective catalytic reduction (SCR) of NO x with NH 3 . These MnFeO x catalysts have been systematically characterized by SEM, TEM, XRD and XPS. Furthermore, the MnFe (0.1) O x showed the highest catalytic performance with nearly 100% of NO x removal efficiency from 200 to 350 °C. On the basis of the TPR, BET and in situ DRIFT results, it can be found that the addition of Fe species induced a possible redox reaction process and increased the surface chemisorbed oxygen concentration and acid sites, which should be responsible for the enhanced SCR activity of MnFe (0.1) O x . Meanwhile, several important process parameters affecting NO x removal efficiency in NH 3 -SCR were carried out, such as time, H 2 O and SO 2 .
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Weiyuan Yao,Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
In this paper, Ce O P material (mainly consisted of CePO 4 ) and TiO 2 supported CeO 2 catalysts were prepared by wet impregnation route for the selective catalytic reduction (SCR) of NO with NH 3 . The SCR activity results had revealed that CeO 2 /Ce O P-0.4 catalyst yielded over than 90% NO conversion within the temperature range of 200–300 °C, whereas the deNO x efficiency of CeO 2 /TiO 2 -0.4 catalyst was less than 30% at 200 °C. After a series of characterization tests, it was found that CeO 2 /Ce O P catalysts were of better dispersion of active phase than CeO 2 /TiO 2 owing to the strong interactions between CeO 2 and surficial Ce O species on Ce O P material. Thus, more active oxygen species could participate in the SCR reaction at low temperature. Furthermore, compared to CeO 2 /TiO 2 sample, the surface acidity was greatly enhanced for CeO 2 /Ce O P catalysts by the introduction of the acidic support, benefiting the adsorption of NH 3 . Both of which were attributed to the main reasons of the promoted SCR performance over CeO 2 /Ce O P catalysts. Moreover, the NO x ad-species on CeO 2 /TiO 2 sample were very stable and could hardly react with adsorbed NH 3 , impeding L-H reaction pathway at low temperature.
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
危险品化学品经营许可证（带存储）