Catalysis Science & Technology
·
2021
·Vol. 11
·期 15
·5125-5134
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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
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
RESEARCH ON CHEMICAL INTERMEDIATES
·
2022
·Vol. 48
·期 7
·3007-3018
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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
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催化材料
✓ 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
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催化化学
✓ 已验证
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
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
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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
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Yanke Yu,Jinsheng Chen,Jinxiu Wang,Yanting Chen
A series of CuSO 4 /TiO 2 catalysts were prepared using a wet impregnation method. The activity of each sample in the selective catalytic reduction of NO by NH 3 (NH 3 -SCR) was determined. The effects of SO 2 and H 2 O, and their combined effect, on the activity were examined at 340 °C for 24 h. The catalysts were characterized using N 2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction of H 2 (H 2 -TPR), temperature-programmed desorption of NH 3 (NH 3 -TPD), and in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS). The CuSO 4 /TiO 2 catalysts had good activities, with low production of N 2 O above 340 °C. SO 2 or a combination of SO 2 and H 2 O had little effect on the activity, and H 2 O caused only a slight decrease in activity during the experimental period. The NH 3 -TPD and H 2 -TPR results showed that CuSO 4 increased the amounts of acid sites and adsorbed oxygen on the catalyst. In situ DRIFTS showed that the NH 3 -SCR reaction on the CuSO 4 /TiO 2 catalysts followed an Eley–Rideal mechanism. The reaction of gaseous NO with NH 3 adsorbed on Lewis acid sites to form N 2 and H 2 O could be the main reaction pathway, and oxygen adsorption might favor this process.
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Yonglong Li,Guobo Li,Yu Zou,Wenming Liu,Hongxiang Zhang,Shengyong Lu,Zhenguo Li,Shule Zhang,Honggen Peng
Developing NH 3 -SCR catalysts possessing excellent NO conversion, N 2 selectivity, and alkali-tolerance at low-temperatures remains a great challenge. MnO x -based catalysts have attracted attention due to their exceptional low-temperature NH 3 -SCR activity. However, their strong oxidative capabilities often lead to excessive NH 3 oxidation , causing a narrow operating temperature window and low N 2 selectivity. In this study, we employed Mo and V to simultaneously fine-tune the acid and redox sites of MnO x , effectively suppressing the excessive NH 3 oxidation at medium-high temperatures. The adjusted Mn 0.90 Mo 0.09 V 0.01 O x catalyst demonstrated excellent low-temperature activity, a significantly broader active temperature window, and robust resistance to alkali metal poisoning. Multiple characterization results indicate that this dual acid-redox sites regulation strategy appropriately weakens the oxidative capacity while notably enhances surface acidity of the catalyst. Furthermore, the combination of in situ DRIFTS and DFT calculations reveal that following the adjustments of Mo and V on MnO x , new Brønsted acid sites are generated. Besides, the regulated catalyst evidently inhibits NO adsorption and nitrate species formation, thus promoting the reaction exclusively through the E-R mechanism, resulting in boosted N 2 selectivity. This study also demonstrates that the optimum NH 3 -SCR performance of catalyst is achieved when oxidation ability and acid sites are harmoniously balanced, rather than following a "stronger is better" trend. In addition, through effective dual-active site regulation, the K-poisoning catalyst retains satisfactory catalytic activity. Thereby, the proposed dual-active sites regulation strategy in this study offers beneficial insights for the development of high-performance denitration catalysts.
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
MOLECULES
·
2023
·Vol. 28
·期 7
·3068
·
IF 4.6
Yuanyuan Ma,Wanting Liu,Zhifang Li,Yuhang Sun,Mingyuan Shi,Zheng Nan,Ruotong Song,Liying Wang,Jingqi Guan
TS-1 zeolite with desirable pore structure, an abundance of acidic sites, and good thermal stability promising as a support for the selective catalytic reduction of NO with NH3(NH3-SCR). Herein, a series of Mn–Fe/TS-1 catalysts have been synthesized, adopting tetraethylenepentamine (TEPA) as a metal complexing agent using the one-pot hydrothermal method. The introduced TEPA can not only increase the loading of active components but also prompts the formation of a hierarchical structure through decreasing the size of TS-1 nanocrystals to produce intercrystalline mesopores during the hydrothermal crystallization process. The optimized Mn–Fe/TS-1(R-2) catalyst shows remarkable NH3-SCR performance. Moreover, it exhibits excellent resistance to H2O and SO2at low temperatures. The characterization results indicate that Mn–Fe/TS-1(R-2) possesses abundant surface Mn4+and Fe2+and chemisorbed oxygen, strong reducibility, and a high Brønsted acid amount. For comparison, Mn–Fe/TiO2displays a narrower active temperature window due to its poor thermostability.Keywords:Mn-Fe/TS-1;one-pot synthesis;NH3-SCR;metal complexing;resistance to H2O and SO2
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yuting Hu,Minghu Zhao,Bo Du,Ting Cheng,Zhaozhong Jiang,Kai Qin,Chengzhu Zhu
A series of M-MnCeO X catalysts using MOF (Metal-organic Framework) were prepared to apply for NH 3 -SCR (Selective Catalytic Reduction) of NO X . The effects of Mn/Ce molar ratio, calcination temperature and its activity including catalytic activity, H 2 O/SO 2 resistance and stability were systematically investigated. The results showed that under the Mn/Ce molar ratio of 1 and calcination temperature of 400 ℃, the catalyst exhibited excellent catalytic activity, H 2 O/SO 2 resistance, and stability. When the concentration of NO was 500 ppm, the gas spatiotemporal velocity (GHSV) was 36,000 h −1 , and the reaction temperature was 100 ℃, the NO conversion efficiency of M-MnCeO X exceeded 90.0 %. Added 200 ppm SO 2 and 3 vol% H 2 O simultaneously, the NO conversion efficiency was close to 80.0 %. By analyzing the physicochemical properties of the catalyst, M-MnCeO X had a large specific surface area, numerous acidic sites, and excellent redox properties. According to density functional theory (DFT), the NH 3 /NO adsorption energy of M-MnCeO X were −2.35 and −2.40 eV, exhibiting lower than a single MOF-derivative, promoting the adsorption of NH 3 or NO. The reaction mechanism on the M-MnCeO X catalyst followed the E-R and L-H mechanisms by In situ DRIFTS.
研究领域:
环境催化
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2020
·
IF 6.146
Xiaona Liu,Yi Cao,Nana Yan,Chao Ma,Lei Cao,Peng Guo,Peng Tian,Zhongmin Liu
The high-temperature (HT) and low-temperature (LT) hydrothermal stabilities of molecular-sieve-based catalysts are important for the selective catalytic reduction of NO x with ammonia (NH 3 -SCR). In this paper, we report a catalyst, Cu 2+ loading SAPO-17, synthesized using cyclohexylamine (CHA), which is commercially available and inexpensive and is utilized in NH 3 -SCR reduction for the first time. After systematic investigations on the optimization of Si and Cu 2+ contents, it was concluded that Cu-SAPO-17-8.0%-0.22 displays favorable catalytic performance, even after being heated at 353 K for 24 h and at 973 K for 16 h. Moreover, the locations of CHAs, host–guest interaction and the Brönsted acid sites were explored by Rietveld refinement against powder X-ray diffraction data of as-made SAPO-17-8.0%. The refinement results showed that two CHAs exist within one eri cage and that the protonated CHA forms a hydrogen bond with O4, which indicates that the proton bonding with O4 will form the Brönsted acid site after the calcination .
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
高影响因子
危险品化学品经营许可证（带存储）