Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Beilei Li,Xiaoxiang Wang,Yaqing Wang,Weijia Wang,Shuguang Zhou,Shihan Zhang,Wei Li,Sujing Li
Elimination of NO x from the non-electric industrial boilers has become priority under the effective implementation of ultra-low emissions. A series of Ce-promoted FeVO 4 catalysts with improved acidity and reducibility have been synthesized in this work. Thereinto, 10Ce/FeVO 4 exhibited an optimum low-temperature performance with 90% of NO x conversion and 95% of N 2 selectivity at 200–300 °C which was kept nearly unchanged with different concentrations of SO 2 ranging from 50 ppm to 200 ppm, showing a superior sulfur tolerance. An array of well-designed experiments has demonstrated that Ce mainly existed as CeVO 4 under a low doping content (1 wt%) on FeVO 4 , which could efficiently increase the amount of acid sites. With more cerium (5–12 wt%) loading on FeVO 4 , the appearance of CeO 2 further resulted in a strong interaction between cerium species and ion species, thus significantly improving the low-temperature catalytic activity . Therefore, the optimum coexistence of CeVO 4 and CeO 2 over 10Ce/FeVO 4 modulated its Brønsted acid and enhanced its redox circulation of Fe 3+ species. Moreover, the NH 3 -SCR reaction pathways of 10Ce/FeVO 4 were broadened from only Eley-Rideal to both Eley-Rideal and Langmiur-Hinshelwood mechanisms after Ce loading on FeVO 4 catalyst. With the presence of SO 2 , the S O/S-O deriving from the generated Ce 2 (SO 4 ) 3 and NH 4 HSO 4 increased the Brønsted acid sites, inducing a satisfying SO 2 tolerance of 10Ce/FeVO 4 catalyst, although the Langmiur-Hinshelwood pathway of 10Ce/FeVO 4 was immediately cut off due to the competitive adsorption of gaseous SO 2 and NO x . This work exemplifies a promising strategy for developing an ideal low-temperature NH 3 -SCR catalyst with good SO 2 resistance.
研究领域:
催化
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2025
·
IF 3.5
Li Xinyu,Li Jingqi,Li Na
This study investigated the effects of sequential acid treatment and phosphorus incorporation on the performance of Fe–Mn-Ce composite metal oxide catalysts. The FeMnCeO x catalyst was prepared using the sol–gel method and modified through two methods: treatment with phosphoric acid alone and a sequential treatment with phosphoric acid followed by sulfuric acid. The results show that the sequentially acid-treated catalyst exhibited over 90% NO x conversion and N 2 selectivity in the temperature range of 200–350 °C, outperforming other catalysts. Characterization analyses such as XRD and NH 3 -TPD revealed that acid modification enhanced the surface acidity and redox properties of catalysts. XPS analysis showed that sequential acid treatment increased the surface chemisorbed oxygen content of the catalyst and optimized its surface structure. In-situ DRIFTS spectroscopy further elucidated that the catalytic reaction follows both Langmuir–Hinshelwood and Eley–Rideal mechanisms concurrently.
研究领域:
环境科学
·
催化化学
·
材料科学
·
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2021
·Vol. 41
·期 1
·166-178
·
IF 4.003
Zhang Bo-Lin,Deng Li-Feng,Liu Bo,Luo Chun-Yun,Liebau Michael,Zhang Shen-Gen,Gläser Roger
Abstract Combining the redox properties of Co and the acid properties of Nb in a Co 3 -Nb-O x catalyst is shown to provide superior performance in the selective catalytic reduction of NO with NH 3 (NH 3 -SCR). Co 3 O 4 shows average activity, however, it exhibits a poor N 2 selectivity. Nb 2 O 5 is not active for NH 3 -SCR. However, the mixed Co 3 -Nb-O x catalyst shows higher NO conversion and N 2 selectivity than the single Co 3 O 4 and Nb 2 O 5 catalysts at 100–300 °C. The results of temperature programmed reduction by H 2 and X-ray photoelectron (XP) spectra indicate that the addition of Nb changes the chemical states of Co and decreases the concentration of Co 3+ and O α , adjusting the activity for catalytic oxidation to a moderate level. This suppresses the formation of undesired N 2 O from the over-oxidation of NH 3 . Incorporation of Co and Nb into one solid synergistically couples their redox behavior and surface acidity, ensuring the high catalytic activity and N 2 selectivity in NH 3 -SCR. Graphical Abstract
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Green Energy & Environment
·
2019
·
IF 0
Ge Li,Baodong Wang,Qi Sun,Wayne Qiang Xu,Ziran Ma,Hongyan Wang,Daojun Zhang,Jiali Zhou
A combined acid–alkali hydrothermal method was used to prepare fly ash –derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia (China). The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m 2 g −1 , the total pore volume was about 0.27 cm 3 g −1 , and the pore size was 0.56 nm; the molar ratios of Al 2 O 3 :P 2 O 5 :SiO 2 were 1:0.86:0.45. Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH 3 (NH 3 -SCR). Powder X-ray diffraction (XRD), N 2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR), NH 3 temperature-programmed desorption (NH 3 -TPD), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), X-ray fluorescence analysis (XRF) and scanning electron microscopy (SEM) were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity. The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading, indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves. The XRF and NMR results showed that replacement by Cu results in more Si islands. The molecular sieve acidity decreased because of the increased number of Si islands. The NH 3 -TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites. SCR activity is closely related to the location of Cu. The 4.47Cu/SAPO-34 catalyst has the highest isolated Cu 2+ showed the highest NH 3 -SCR activities (> 90%) at 250–350 °C. This work opens up new avenues for recycling fly ash formed in coal-fired power plants (reducing environmental pollution) and developing low-cost SCR catalysts for NO x pollution control.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
Molecular Catalysis
·
2025
·
IF 4.9
Qiuju Qin,Chaolian Zhu,Donghai Mo,Zhengjun Chen,Lihui Dong,Bin Li,Liya Zhou
MnO x exhibits excellent low temperature activity for degradation NO x , but its poor SO 2 tolerance restrains its application. Herein, an in situ construction method for MnO x loading on Mn-doped ZrO 2 carrier with carbon (MnO x /Mn-ZrO 2 -C) derived from Mn(NO 3 ) 2 /UIO-66 by in situ doped pyrolysis–oxidation, in which Mn replaces Zr to modify the electronic structure of the ZrO 2 . The MnO x /Mn-ZrO 2 -C with abundant surface oxygen and acid sites showed excellent activity and better SO 2 resistance. A series of characterization results indicated that Mn doping modulates the electron structure of carrier ZrO 2 and enhances the interactions among MnO x , carbon, and Mn-ZrO 2 , resulting in increasing the electron cloud density around Mn and Zr, and consequently, the Mn and Zr on the MnO x /Mn-ZrO 2 -C exhibit poorer sulfiphilic. These findings emphasize the benefits of utilizing a multipronged effect to fabricate highly active and sulfur-resistant NH 3 -SCR catalysts.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2026
·
IF 9
Bo Song,Zhenxing Shen,Zitong Wang,Qin Peng,Jia Liu
Traditional Mn-based NH 3 -SCR catalysts have a narrow temperature window, limiting low-temperature use. In this work, Mn@N-7 was prepared by a simple hydrothermal method using potassium permanganate and urea. The hydrothermal conditions are much milder than those used for most Mn-based catalysts. Graphite felt (GF) serves as a green support, providing a 3D carbon fiber network for uniform growth of manganese oxide nanowebs. Its high surface area (83.10 m 2 g −1 ) and open channels promote active species dispersion and fast mass transfer. The strong carbon framework prevents sintering at high temperatures. Mn@N-7 shows nearly 100% NO conversion at 100–200 °C and maintains good activity for 30 h. Its estimated cost is 1.2–1.8 USD kg −1 , lower than 3.0–4.5 USD kg −1 for V 2 O 5 -WO 3 /TiO 2 catalysts. The mild hydrothermal process avoids high-temperature calcination. This work demonstrates GF is a sustainable support and offers guidance for carbon-based catalysts in clean air applications.
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 20
·5958
·
IF 3.623
Xusheng Ren,Zhiliang Ou,Bang Wu
The activated coke is a promising support for catalysts, and it is important to study the performance of the activated coke catalyst on the removal of NOx. In the current research, a series of the activated coke-supported Mn–Cu catalysts are prepared by the incipient wetness impregnation method. The effects of the molar ration of Mn/Cu, the content of Mn–Cu, the calcination temperature, and reaction space velocity on NO conversion are investigated, and it was found that the 8 wt.% Mn0.7Cu0.3/AC had the best catalytic activity when the calcination temperature was 200 °C. The existence of SO2caused the catalyst to deactivate, but the activity of the poisoning catalyst could be recovered by different regeneration methods. To uncover the underlying mechanism, BET, XPS, XRD, SEM and FTIR characterizations were performed. These results suggested that the specific surface area and total pore volume of the poisoning catalyst are recovered and the sulfite and sulfate on the surface of the poisoning catalysts are removed after water washing regeneration. More importantly, the water washing regeneration returns the value of Mn3+/Mn4+, Cu2+/Cu+, and Oα/Oβ, related to the activity, basically back to the level of the fresh catalyst. Thus, the effect of water washing regeneration is better than thermal regeneration. These results could provide some helpful information for the design and development of the SCR catalysts.Keywords:activated coke;low-temperature NH3-SCR;sulfur poisoning;regeneration
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Zhifei Hao,Guoquan Liu,Nan Ma,He Zhang,Yi Li,Yuguo Xia,Dongpeng Zhang,Sihui Zhan
Acidity and redox properties of the catalyst are two crucial factors affecting the performance of NH 3 -SCR. Herein, we design a novel WO x /Cu-CeO 2 oxide catalyst in which the WO x species are highly dispersed on the {111}/{100}-terminated surface of Cu-doped CeO 2 nanospheres , which exhibits great deNO x activity advantage and wide operating temperature window (200–400 °C, over 85% NO x conversion with a gas hourly space velocity (GHSV) of 60,000 h −1 ), as well as good sulfur resistance and N 2 selectivity . The relationship among the composition, acidity and redox properties of the WO x /Cu-CeO 2 catalyst is established in the NH 3 -SCR reaction. The combined experimental studies and spectroscopic characterization reveal that the introduction of Cu into the lattice of CeO 2 not only increases the surface Ce 3+ and oxygen vacancy concentration but also provides more sites for capture and dispersion of WO x species, thus mediating and improving the Lewis and Brønsted acid sites and reducibility of catalyst. XPS and DFT calculations further demonstrate that electronic interaction between WO x and Cu-doped CeO 2 is enhanced duo to the existence of interactions of short-range Ce-O-Cu and Ce-O-W. Moreover, the NH 3 -SCR reaction over WO x /Cu-CeO 2 may follow both Langmuir-Hinshelwood and Eley-Rideal reaction pathway according to the in situ DRIFTS.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Wenqi Liu,Jingyan Zhang,Mei Dong,Zhaoyi Ding,Qunfei Wang,Fanghao Ning,Qin He,Yanyan Chen,Zhen Zhao,Zhongfu Li,Conghua Liu
Low-silica chabazite (CHA) catalysts with varying configurations of Cu 2+ -2Z and [Cu(OH)] + -Z active centers are developed through the regulation of the opening of CHA-cages. The catalysts are subsequently applied to the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR) reactions. A series of characterizations and performance evaluations indicate that the density of [Cu(OH)] + -Z in eight-member rings (8MRs) is positively correlated with low-temperature performance. Moreover, the presence of partial Cu 2+ -2Z in six-member rings (6MRs) enhances activity and tolerance at high temperatures. The residual K + ions in the CHA-cages after NH 4 + exchange are retained in the 6MRs. Density functional theory calculations demonstrate that the residual K + ions stabilize the 6MRs structure, ensuring the entry and stable presence of the active Cu 2+ -2Z centers. In situ analysis reveals the reaction intermediates involved in the NH 3 -SCR process on representative catalysts. These findings can further elucidate the active centers of CHA-type catalysts and guide the design of commercial catalysts.
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
·
2024
·
IF 7.4
Yanli Zhang,Jian Li,Jianyu Cai,Shuangye Li,Xing Fan,Liyun Song,Ruixue Guo,Jiasheng Liu
In this study, a series of γ-Fe 2 O 3 -modified V 2 O 5 -MoO 3 /TiO 2 (VMT) catalysts was prepared by wet impregnation method. The γ-Fe 2 O 3 -modified catalysts exhibited excellent catalytic performance, and 1.25 wt% γ-Fe 2 O 3 content improved the deNO x efficiency at 150 °C from 54% (unmodified VMT catalyst) to 84% (modified catalyst). BET, XRD, XPS, NH 3 -TPD, H 2 -TPR, and in situ DRIFTs were employed to characterize the physicochemical properties and reaction mechanisms of the catalysts. The introduction of γ-Fe 2 O 3 increased the V 5+ /V 4+ ratio, surface chemisorbed oxygen content, redox ability, and a number of acid sites in the prepared catalysts. XPS confirmed the addition of γ-Fe 2 O 3 introduced new charge transfer pathways (Fe 3+ /Fe 2+ ↔ V 5+ /V 4+ ). In situ DRIFTs suggested that the addition of γ-Fe 2 O 3 to the catalyst significantly increased the adsorption capacity of catalyst for NH 3 and NO x , while also exerting a strong activating effect on the adsorbed NH 3 . Furthermore, selective catalytic reduction over the VMT and 5PEG@1.25Fe-VMT catalysts followed the Eley-Rideal (E-R) mechanism. At temperatures above 200 °C, the 5PEG@1.25Fe-VMT catalyst also followed the Langmuir-Hinshelwood (L-H) mechanism.
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 COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Yiqing Zeng,Yanan Wang,Shule Zhang,Qin Zhong,Weilong Rong,Xiaohai Li
In this work, novel (CeO 2 ) x -(CePO 4 ) 1−x (defined as Ce x P 1−x ) nanorod composites were prepared by a simple co-precipitation method, and the influence of CeO 2 on the catalytic performance of CePO 4 for selective catalytic reduction of NO by NH 3 (NH 3 -SCR of NO) was investigated. The catalytic performance evaluation revealed that the Ce x P 1−x catalysts, especially Ce 0.2 P 0.8 exhibited a much better catalytic activity and H 2 O + SO 2 resistance than CePO 4 . Structure characterizations via high-resolution transmission electron microscope (HRTEM) and Brunauer-Emmett-Teller (BET) revealed that the introduction of CeO 2 had a little effect on the shape of CePO 4 nanorods and it could promote the formation of new mesoporous then significantly enhance the surface area of catalyst. The analysis results of active sites suggested that phosphorus was the main adsorption site for NH 3 and the redox sites were controlled by CeO 2 on Ce x P 1−x catalysts. Finally, reaction process study demonstrated that the NH 3 -SCR over Ce x P 1−x was processed via Langmuir-Hinshelwood (L-H) mechanism. Combining the results of active sites and reaction mechanism analysis, it was drawn that the superior low temperature activity of Ce x P 1−x could be attributed to its excellent redox properties, which promoted the oxidation of NO then facilitated the process of NH 3 -SCR via “fast SCR”.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Jiancheng Wang,Zhaoliang Peng,Ying Chen,Weiren Bao,Liping Chang,Gang Feng
Cu-SSZ-13/cordierite monolithic catalyst was prepared by in situ hydrothermal synthesis method. The physicochemical properties of the as-prepared Cu-SSZ-13/cordierite were investigated by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, N 2 -adsorption, inductively coupled plasma, X-ray photoelectron spectroscopy, and solid-state NMR techniques. The removal of nitrogen oxides (NO x ) from simulated diesel vehicle exhaust gas was performed using fixed-bed reactor. The effects of crystallization time and addition of HF during hydrothermal synthesis, reaction space velocity, and aging treatment of catalyst on the catalytic performances of NO x reduction reactions were investigated. The results indicate that the optimum crystallization time was 72 h. Highly crystalline structure of zeolite Cu-SSZ-13 was formed, in a close combination with a carrier, via one step hydrothermal process. Cu-SSZ-13/cordierite showed excellent DeNO x performance for selective catalytic reduction (SCR) and anti-aging properties in a simulated diesel exhaust gas under a high space velocity. At a high space velocity of 72,000 h −1 , the highest conversion and N 2 selectivity of 94% and 90%, respectively, were achieved. After the aging for 50 h at 720 °C, NO x reduction rate was still >80% in the temperature range of 350–550 °C. The larger height to diameter ratio of the same catalysts enhanced the NH 3 -SCR catalytic activity and broadened the active temperature window. The addition of HF increased the catalytic activity and anti-aging performance of the sample.
研究领域:
催化材料
·
环境科学
·
化学工程
✓ 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）