JOURNAL OF THE ENERGY INSTITUTE
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2022
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IF 6.47
Pijun Gong,Feng He,Junlin Xie,Haitao Wu
Zn species that exist in the flue gas are dangerous toxicants for SCR catalysts, which will seriously damage its catalytic activity and service life. Hence, the multi-layered nanosheets γ-Al 2 O 3 with (110) facets were introduced into the CeTiOx catalyst to improve the Zn-poisoning resistance performance. Benefiting from the structural and compositional merits, as well as the superior reducibility, abundant acid sites, and chemisorbed oxygen, the 3%Zn–Ce 0.3 -Al 0.4 -Ti catalyst with multi-layered nanosheets structure exhibits excellent NH 3 -SCR activity, over 90% NO conversion between 240 °C and 340 °C. In addition, in situ DRIFTS results suggest the SCR reaction mainly follows L-H and E-R mechanisms on 3%-Ce 0.3 -Al 0.4 -Ti samples, result from the multi-layered nanosheets γ-Al 2 O structure improves the BET specific surface area and Ce 3+ , promotes the adsorption/activation of more NH 3 and NOx species. More interestingly, compared with CeO 2 and TiO 2 the Zn species prefer to absorbed on nanosheets γ-Al 2 O 3 with (110) facets, so it can effectively protect CeO 2 from poisoning as a sacrificial agent .
研究领域:
环境科学
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催化材料
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
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IF 7.149
Fei Wang,Zhibo Xie,Jinsheng Liang,Baizeng Fang,Yu’ang Piao,Ming Hao,Zishuo Wang
Low temperature NH3 selective catalytic reduction (NH3-SCR) technology is an efficient and economical strategy for cutting NOx emissions from power-generating equipment. In this study, a novel and highly efficient NH3-SCR catalyst, tourmaline-modified FeMnTiOx is presented, which was synthesized by a simple one-step sol–gel method. We found that the amount of tourmaline has an important impact on the catalytic performance of the modified FeMnTiOx-based catalysts, and the NOx conversion exceeded 80% from 160 to 380 °C with the addition of 5 wt % tourmaline. Compared with the pure FeMnTiOx, the catalytic efficiency at a temperature below 100 °C was increased by nearly 18.9%, and the operation temperature window was broadened significantly. The enhanced catalytic performance of the FeMnTiOx catalyst was mainly attributed to the small spherical nanoparticles structure around the tourmaline powders, resulting in the increased content of Mn3+, Mn4+, and chemical oxygen on the catalytic surface. These as-developed tourmaline-modified FeMnTiOx materials have been demonstrated to be promising as a new type highly efficient low temperature NH3-SCR catalyst.
研究领域:
环境科学
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催化材料
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能源工程
✓ 已验证
DOI
PubMed
高影响因子
Nanomaterials
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2020
·Vol. 10
·期 11
·2170
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IF 4.324
Jialing Chen,Gang Peng,Tingyu Liang,Wenbo Zhang,Wei Zheng,Haoran Zhao,Li Guo,Xiaoqin Wu
The NH3-SCR activities and hydrothermal stabilities of fivexCu/MCM-22 zeolites with different Cu loadings (x= 2–10 wt%) prepared by incipient wetness impregnation method were systematically investigated. The physicochemical properties ofxCu/MCM-22 zeolites were analyzed by XRD, nitrogen physisorption, ICP-AES, SEM, NH3-TPD, UV-vis, H2-TPR and XPS experiments. The Cu species existing inxCu/MCM-22 are mainly isolated Cu2+, CuOxand unreducible copper species. The concentrations of both isolated Cu2+and CuOxspecies inxCu/MCM-22 increase with Cu contents, but the increment of CuOxspecies is more distinct, especially in high Cu loadings (>4 wt%). NH3-SCR experimental results demonstrated that the activity ofxCu/MCM-22 is sensitive to Cu content at low Cu loadings (≤4 wt%). When the Cu loading exceeds 4 wt%, the NH3-SCR activity ofxCu/MCM-22 is irrelevant to Cu content due to the severe pore blockage effects caused by aggregated CuOxspecies. Among the fivexCu/MCM-22 zeolites, 4Cu/MCM-22 with moderate Cu content has the best NH3-SCR performance, which displays higher than 80% NOxconversions in a wide temperature window (160–430 °C). Furthermore, the hydrothermal aging experiments (xCu/MCM-22 was treated at 750 °C for 10 h under 10% water vapor atmosphere) illustrated that all thexCu/MCM-22 zeolites exhibit high hydrothermal stability in NH3-SCR reactions.Keywords:Cu/MCM-22;NH3-SCR;Cu loading;hydrothermal aging
研究领域:
催化化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
ACS Catalysis
·
2025
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IF 13.1
Zhiying Liu,Meiqing Shen,Shuhuan Wang,Chunjuan Zhang,Jun Wang,Wei Li,Feng Gao
To elucidate how CeO2 additives enhance the activity and stability of Cu-SSZ-13 SCR catalysts, we investigated two CeO2/Cu-SSZ-13 composite catalysts with Cu loadings of 1.0 and 2.5 wt %. These catalysts were characterized using an array of techniques, including XRD, SEM, TEM, NMR, H2-TPR, NH3-TPD, DRIFTS, DFT and SCR reactions under both steady-state and transient kinetic analysis conditions. Our findings demonstrate that CeO2 promotes low-temperature SCR by forming exchanged, isolated Ce-ions, which enhance Cu-ion coupling efficiency. External surface CeO2 particles can convert NO + O2 to surface nitrates, but these species primarily act as spectators below ∼250 °C, and do not contribute to the enhancement of low-temperature SCR activity. In contrast, these surface CeO2 particles can synergizes with Brønsted acid sites (BAS) to elevate high-temperature SCR activity. Furthermore, hydrothermal stability and sulfur resistance are improved by the presence of external surface CeO2 particles, a benefit that applies irrespective of Cu loading.
研究领域:
催化
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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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表面科学
✓ 已验证
DOI
高影响因子
Catalysts
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2020
·Vol. 10
·期 3
·311
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IF 3.52
Jing Shao,Shuyuan Cheng,Zhaoxu Li,Bichun Huang
A ZSM-5 zeolite with a hierarchical pore structure was synthesized by the desilication-recrystallization method using tetraethyl ammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) as the desilication and structure-directing agents, respectively. The MnOx/ZSM-5 catalyst was synthesized by the ethanol dispersion method and applied for the low-temperature selective catalytic reduction of NOxwith NH3. The results showed that NOxconversion of the hierarchical MnOx/ZSM-5 catalyst could reach 100% at about 120 °C and could be maintained in the temperature range of 120–240 °C with N2selectivity over 90%. Furthermore, the hierarchical MnOx/ZSM-5catalyst presented better SO2resistance performance than the traditional catalyst in the presence of 100 ppm SO2at 120 °C. XRD, SEM, TEM, XPS, BET, NH3-TPD, and TG were applied to characterize the structural properties of the MnOx/ZSM-5 catalysts. These results showed that the MnOx/ZSM-5 catalyst had micropores (0.78 nm) and mesopores (3.2 nm) leading to a larger specific surface area, which improved the mass transfer of reactants and products while reducing the formation of sulfates. The better catalytic performance over hierarchical MnOx/ZSM-5 catalyst could be attributed to the higher concentration of Mn4+and chemisorbed oxygen species and higher surface acidity. The improved SO2resistance was related to the catalyst’s hierarchical pore structure.Keywords:hierarchical pore structure;MnOx/ZSM-5;NH3-SCR;SO2resistance
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
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IF 3.375
Siqian Zhang,Cheng Zhang,Qiang Wang,Wha-Seung Ahn
A series of ZSM-5 catalysts were synthesized using fly ash from power plants and red mud from aluminum production in different weight ratios. The ZSM-5 was subsequently coimpregnated with Co and Mn and tested for the low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR). These catalysts were characterized by XRD, N2-adsorption isotherms, SEM, XPS, and H2-TPR. Among all the prepared catalysts, 5 wt % Co 10 wt % Mn/ZSM-5 had shown the best catalytic activity, with 98.8% conversion of NOx and 90.7% selectivity toward N2 at 150 °C. This is comparable to the performance of a similar ZSM-5 catalyst prepared using chemical reagents. The high ratio of Mn4+/(Mn4+ + Mn3+ + Mn2+) in the catalyst improved the NOx conversion, whereas the moderate redox property imparted by Co3+ led to high N2 selectivity. This catalyst also showed strong resistance against poisoning in 100 ppm SO2 and 5% H2O. This work demonstrates that effective NOx removal treatment with high N2 selectivity and sufficient stability for either cement plants or incinerators can be achieved by using a porous catalyst/support material produced from industrial solid wastes.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
RSC Advances
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2017
·Vol. 7
·期 84
·53622-53630
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IF 3.108
Changming Li,Hong Zeng,Pingle Liu,Jian Yu,Feng Guo,Guangwen Xu,Zhan-guo Zhang
The development of new routes for the utilization of red mud (RM) waste is very urgent due to its huge accumulation and potential environmental harm. By taking advantage of its Fe–Al–Si–Ti composition and excellent plasticity, we developed a ball milling and acid–base neutralization method to reuse the RM waste as Fe-based denitration catalysts. The resulting RM catalysts demonstrate excellent catalytic activity and stability with >90% NO conversion above 400 °C in the presence of SO2 and H2O, which is even much better than that of a commercial V–W–Ti catalyst. Characterization data reveal that our treatment eliminates poisonous alkaline metal elements and increases dispersion of RM particles, making the RM active for denitration reactions. The formation of ferric sulfate species with more reducible Fe3+/Fe2+ active sites by a SO2 activation method can further enhance the denitration activity. Moreover, NH3-TPD and in situ IR results demonstrate that the NH3-SCR reaction over the RM catalyst follows the Eley–Rideal mechanism at high temperature and the increased absorption of NH3 for alkaline metal-eliminated or SO2-activated samples accounts for its high DeNOx efficiency. The demonstrated feasibility for reusage of the RM as DeNOx catalyst has promising industrial prospects for its extremely low cost, no toxicity, and high efficiency.
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 JOURNAL
·
2021
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IF 13.273
Peng Lu,Lyumeng Ye,Xianhui Yan,Ping Fang,Xiongbo Chen,Dingsheng Chen,Chaoping Cen
Increasing attentions have been drawn towards the simultaneous removal of toluene in current existing NH 3 -SCR unit. The development of dual-functional catalysts and the understanding of impact induced by toluene addition are momentous but lacking. Herein, a well-reported MnO x -CeO 2 catalyst was chosen as active phase to assess the role of HZSM-5 in this simultaneous removal process. HZSM-5 was found to supply more acid sites especially Lewis acid on the MnO x -CeO 2 catalyst. A MnCe/HZSM-5 catalyst with a SiO 2 /Al 2 O 3 molar ratio of 25 delivered a broad active temperature window of 200–400 °C with NO conversion > 80% and possessed a stable N 2 selectivity > 96% in NH 3 -SCR reaction. Also, it was able to maintain above 60% of toluene conversion in the range of 200–400 °C. More Lewis acid sites, together with abundant Mn 4+ , Ce 3+ and active surface oxygen that formed via the interaction between Mn 4+ /Mn 3+ and Ce 4+ /Ce 3+ (Mn 3+ + Ce 4+ ↔ Mn 4+ + Ce 3+ ), contributed to the superior catalytic performance of MnCe/HZSM-5 with lower SiO 2 /Al 2 O 3 ratio. A reversible catalyst deactivation in NH 3 -SCR induced by toluene was found. Toluene was prone to reacting with NH 3 forming nitriles, which infringed the active sites and decreased the available coordinated NH 3 on Lewis acid sites. In addition, the suppression of NO oxidation to NO 2 that decreasing the percentage of “fast SCR” process, and the inhibition of NH 3 activation to NH 2 species also contributed to the lower SCR activity in the presence of toluene over MnCe/HZSM-5.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2023
·
IF 4.9
Songil Sin,Jiawei Ji,Lijun Cheng,Zhiwen Gu,Chong Tan,Kwangchol Ri,Changjin Tang
CeO 2 -based catalysts are widely investigated for selective catalytic reduction (SCR) of NO with NH 3 . Interaction of NO/O 2 with CeO 2 generally produces two surface species, i.e., nitrates and nitrites. However, the explicit quantification of these two species is still unresolved. Herein, we reported that spectrophotometry characterization was effective in determining surface adsorbed NO x species on CeO 2 by measuring the corresponding ions (NO 2 – and NO 3 – ) dissolved in aqueous solution. Experimental results show that both nitrate (–NO 3 ) and nitrite (–NO 2 ) species can be quantitatively evaluated and the accuracy is verified by calibrating with NO x -TPD result. Exclusive transfer of adsorbed NO x from catalyst surface to aqueous solution is confirmed and the dissolution process can be accelerated by ultrasonic treatment. Moreover, useful information related to evolution of surface NO x species under various conditions (O 2 treatment, different adsorption temperature and duration) and over different catalysts (Fe 2 O 3 , MnO 2 and MnO x –CeO 2 ) are provided. The result of present study demonstrates the potential of spectrophotometry for quantitative discrimination of surface NO x species on CeO 2 and other oxide-based materials, which is conducive to mechanism analysis of SCR reaction.
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
FUEL
·
2023
·
IF 7.4
Xin Guo,Zhiyong Ding,Na Kang,Liu Yang,Yuanjiang Wang,Cheng Zhang,Zhaoqiang Li,Tiantian Zhang,Yan Wang,Yu Wang,Hao Qu
The zeolite-based catalyst is a promising option for the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) due to its low toxicity. However, the challenge lies in its low-temperature activity. This study developed a multi-component catalytic system consisting of Ce/Mn/Cu-loaded Beta zeolite to reduce NO x . With fixed contents of Cu and Mn, we investigated the NH 3 -SCR process and the mechanism of action of the rare-earth species (i.e., Ce) in the system. Upon optimization of the content of Ce, the Ce/Mn/Cu-loaded Beta zeolite demonstrated enhanced low-temperature activity compared to samples loaded with Cu or Cu/Mn in the temperature range of 150–250 °C. When Ce was loaded in an appropriate proportion, it regulated the oxidation state of Cu, optimizing active adsorption species for NO and strengthening the strength of Brønsted acid sites in the catalyst. These synergetic effects led to improved NH 3 -SCR catalytic performance. This study can contribute to a better understanding of multiple metal-loaded zeolites in the NH 3 -SCR process and inform future design of Beta-type 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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Qinyu Zhou,Chong Tan,Tianfa Tang,Yu Wang,Siyuan Li,Meilin Tao,Hongliang Zhang,Liu Yang,Changjin Tang
The occurrence of NH 3 over-oxidation represents one intractable challenge for the effective application of NH 3 -SCR technology. Herein, a rational NO x activation strategy was innovatively proposed to counteract NH 3 over-oxidation during high temperature NH 3 -SCR. As a proof of concept, the hybrid catalyst of CeO 2 -ZSM-5 was explored. It was shown that the activity of CeO 2 in NH 3 -SCR was profoundly improved via physically mixing with ZSM-5, achieving more than 85 % NO at 500 °C, in sharp contrast to the negative NO conversion present for pristine CeO 2 . Comprehensive characterizations from NH 3 -TPD, NO-TPD and in situ DRIFTS verified the negligible modification of NH 3 oxidation but significant alteration of surface NO x . Due to the facile NO x activation, the reaction of NH 3 + NO x overwhelms that of NH 3 + O 2 , leading to the obtainment of excellent high temperature NH 3 -SCR performance. The novel strategy reported here is expected to provide valuable guidance for designing NH 3 -SCR catalysts with superior high temperature performance.
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
·
2022
·
IF 16.744
Xiaolei Hu,Weiye Qu,Junxiao Chen,Dongrun Xu,Jing Liu,Yangyang Dong,Rui Liu,Zhen Ma,Xingfu Tang
Selective catalytic reduction (SCR) of NO x with NH 3 over V 2 O 5 -based catalysts has been widely used to control NO x emissions from power plants, but its application is largely limited in other industrial boilers because of insufficient catalytic efficiency at low temperatures. Here we resolve this problem by mechanistically designing a highly active Ce-W/TiO 2 catalyst with reactants-coupling dual catalytic sites. The results demonstrate that W and Ce are highly dispersed on the surfaces of Ce-W/TiO 2 to form dual catalytic sites, which act as acid-base pairs favorable for NH 3 and NO adsorption, respectively, thereby allowing the reaction of adsorbed NH 3 on the W site with oxidized NO species (NO 3 − ) adsorbed on the adjacent Ce site to proceed along a low-activation-energy pathway via Langmuir-Hinshelwood mechanism. Compared with Ce/TiO 2 , a W-Ce synergy gives rise to more abundant Ce 3+ on Ce-W/TiO 2 , which facilitates the activation of O 2 during SCR process, thus improving the low-temperature SCR performance. Therefore, the design of the dual catalytic sites based on the properties of reactants provides an alternative approach to developing highly active SCR catalysts.
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）