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
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 84
·53622-53630
·
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
FUEL
·
2022
·
IF 8.035
Yangfan Chen,Hongyan Yan,Wenxin Teng,Jiangling Li,Weizao Liu,Shan Ren,Jian Yang,Qingcai Liu
NH 3 -SCR technology with commercialized V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalysts has become the most efficient technology for the removal of NO x from coal-fired power plants. However, the weaknesses of V 2 O 5 -WO 3 (MoO 3 )/TiO 2 catalysts such as the biotoxicity of vanadium species and high cost restrict their increased applicability. Fe 2 O 3 -based NH 3 -SCR catalysts show potential in placing traditional catalysts due to their good N 2 selectivity, excellent environmentally friendly performance, high thermal stability, and low cost. In this work, low cost Fe 2 O 3 -containing solid waste was exploited as the base material for NH 3 -SCR catalyst preparing. Moreover, bulk MoO 3 and MoO 3-x nanosheets decorated Fe 2 O 3 composite NH 3 -SCR catalysts were synthesized and both revealed conspicuously improved NO x removal efficiency compared with bare-Fe 2 O 3 catalyst. However, the N 2 selectivity of these two catalysts showed significant differences. Therefore, comprehensive characterizations, NH 3 oxidation experiments, and in-situ diffusion Fourier transform infrared spectroscopy (DRIFTS) experiments were performed to determine the N 2 O formation pathways of the above two catalysts. The redox properties were highly related to the N 2 O generated from NH 3 oxidation. Moreover, the huge difference in NH 3 and NO adsorption ability led to disparate reaction mechanisms over the two catalysts. This new understanding of the N 2 O formation mechanism has the potential to guide the rational design of improved NH 3 -SCR catalysts suffering from low N 2 selectivity.
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
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
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
·
能源工程
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Jingang Wang,Jianbo Zhang,Cheng Xing,Taosheng Jin,Jinpeng Liu,Meiting Ju,Xuejiao Tang
Phosphorus (P) poisoning of NH 3 -SCR catalysts is inevitable in application of NO x abatement of diesel exhaust. The distinct effects on Cu-SSZ-13 of P from different precursors (H 3 PO 4 and (NH 4 ) 2 HPO 4 ) were figured out and the mechanism was further investigated. P-poisoned Cu-SSZ-13 (Si/Al = 6) catalysts were prepared and characterized using N 2 adsorption, X-ray powder diffraction (XRD), scanning electron microscope with energy-dispersive X-ray spectroscopy mapping (SEM-EDX), ammonia temperature-programmed desorption (NH 3 -TPD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature programmed reduction (H 2 -TPR), electron paramagnetic resonance (EPR) and 27 Al solid-state magic angle spinning nuclear magnetic resonance spectroscopies ( 27 Al NMR). Significant enhancement of high-temperature activities (400–600 °C) were observed for the catalysts with P loading of 0.3–0.9 wt%, since the appropriate incorporation enabled to bind P atoms to CuO x in remained framework. However, the high P content of 1.5 wt% resulted in a detrimental effect on framework to induce the accumulation of Cu species. Interestingly, the dominant P from H 3 PO 4 was inclined to directly attack the framework Al leading to more severe dealumination, while the P from (NH 4 ) 2 HPO 4 interacted with Cu 2+ to form copper phosphate with more Cu 2+ migrating to the surface of the catalyst which promoted the NO x conversation at each active site resulting in the low-temperature catalytic activity unchanged. So, control of the P/Cu and form of P is capable of preventing P poisoning and unlocks the potential of Cu-SSZ-13 in exhaust treatment.
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
·
2014
·
IF 6.007
Fredrik Gunnarsson,Moa Z. Granlund,Mattias Englund,Jazaer Dawody,Lars J. Pettersson,Hanna Härelind
We report on a high NO x reduction activity over Ag/Al 2 O 3 catalysts, using hydrogen produced in a fuel reformer. The focus of the study is to evaluate the performance of a hydrocarbon selective catalytic reduction (HC-SCR) catalyst in real conditions. Initially, the catalytic materials for the fuel reformer (Rh/CeO 2 -ZrO 2 ) and the HC-SCR (Ag/Al 2 O 3 ) were evaluated in separate bench-scale reactor setups. These two setups were subsequently joined into an integrated bench-scale reactor setup with the aim to evaluate the influence of the reformate on the HC-SCR activity in a controlled environment. In the final phase of the study a 4 wt.% Ag/Al 2 O 3 catalyst doped with 100 ppm(w) Pt was scaled up and tested in a pilot-scale reactor setup. The pilot-scale reactor setup enabled evaluation of the HC-SCR activity in real exhaust gases generated by a single cylinder engine (genset) together with a hydrogen-rich gas supplied from a fuel reformer. Commercial biodiesel (NExBTL) was used as reducing agent for the HC-SCR as well as fuel in the fuel reformer for both the bench-scale and pilot-scale experiments. This study gives an excellent link between evaluations of the catalytic materials, controlled bench-scale experiments and applied engine experiments, proving a viable concept for lean NO x reduction together with onboard hydrogen production. A NO x conversion of above 70% was reached at temperatures below 250 °C, in bench-scale experiments when hydrogen produced in the fuel reformer is added.
研究领域:
环境科学
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催化化学
·
能源工程
✓ 已验证
DOI
高影响因子
Processes
·
2021
·Vol. 9
·期 11
·1923
·
IF 2.847
Bo Wang,Qiaowen Yang
Every year, large amounts of selective catalytic reduction (SCR) catalysts with losing catalytic activity and failing to be regenerated need to be regenerated, which will result in acute pollution. Recycling valuable metals from spent SCR catalysts can not only solve environmental problems, but also save resources. The process of sodium roasting and water leaching is able to effectively extract vanadium (V) and tungsten (W) from spent SCR catalysts. To improve the efficiencies of V and W, different sodium additives were first investigated in the roasting process. The results revealed that the process of NaCl-NaOH composite roasting and water leaching showed superior leaching efficiencies of V and W, which can reach 91.39% and 98.26%, respectively, and simultaneously, it can be found that adding low melting point NaOH promoted mass transfer as compared with the melting points of different sodium additives. Next, a single-factor experiment was conducted to investigate different roasting conditions, such as roasting temperature, roasting time, mass ratio of sodium additive and catalyst, and mass ratio of NaCl and NaOH, on the leaching efficiencies of V and W. Then, a three-level and four-factor orthogonal experiment and a weight matrix analysis were used to optimize the roasting parameters. The results showed that roasting temperature had the most significant effect on the leaching efficiencies of V and W, and the optimal roasting conditions were as follows: the roasting temperature was 750 °C, the roasting time was 2.5 h, the mass ratio of sodium additive and catalyst was 2.5, and the mass ratio of NaCl and NaOH was 1.5. Under the optimal roasting conditions, the leaching efficiencies of V and W were 93.25% and 99.17%, respectively. The results of XRD analysis inferred that VO2coming from the decomposition of VOSO4in spent SCR catalysts may first oxidize into V2O5and then react with sodium additives to produce NaVO3. The formation of titanium-vanadium oxide ((Ti0.5V0.5)2O3) was a part reason of hindering the leaching of vanadium. With the increase of roasting temperature, TiO2converted into Na2Ti3O7, which indicated that the main structure of the catalyst was destroyed, and simultaneously, more characteristic peaks of sodium metavanadate and sodium tungstate appeared, thus enhancing the leaching of V and W. Finally, it can be seen that the process of NaCl-NaOH roasting and water leaching remained higher leaching efficiencies of V and W and lower roasting temperature by comparing with leaching efficiencies of V and W in different processes of recycling SCR catalyst. The process of NaCl-NaOH composite roasting and water leaching provided a strategy with a highly efficient and clean route to leach V and W from spent SCR catalyst. The orthogonal experiment and weight matrix analysis in our study can be used as a reference to optimize the reaction conditions of a multiple indexes experiment.
研究领域:
环境科学
·
冶金工程
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2025
·
IF 6.6
Zhenyun Tian,Weichao Zheng,Liu Yang,ChuanMing Wu,Jialong Kang,Jiawen Chen,Guibao Qiu
The recovery of valuable metals from spent SCR catalysts currently centers on chromium and tungsten oxides. However, this approach demands substantial consumption of acids and bases, and due to the low vanadium and tungsten content, its economic output is minimal. In contrast, titanium dioxide, which exists in significantly higher proportions within the catalyst, is largely overlooked, aggravating environmental issues and leading to considerable resource wastage. This research proposes utilizing spent SCR catalysts as raw materials to directly synthesize titanium alloys, thereby increasing the recovery value of these discarded materials. The findings reveal that aluminum, employed as a reducing agent, efficiently reduces the majority of valuable metals in the catalyst, resulting in the formation of titanium alloys. Furthermore, the addition of calcium oxide markedly enhances the reduction process and improves slag-metal separation. When the CaO content reaches 50 wt%, titanium recovery achieves an impressive rate of 93.34 wt%. The produced alloy comprises primarily a Ti–Al alloy matrix, with a Ti–Si alloy as a dispersed reinforcing phase uniformly distributed within the matrix, demonstrating significant potential for practical applications.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Nanomaterials
·
2017
·
IF 1.871
Ke Yang,Weiwei Xiao,Quan Xu,Jiaojiao Bai,Yan Luo,Hao Guo,Li Cao,Wei Cai,Peng Pu,Lulu Cai
Typical p-type semiconductor MnO codoped with n-type semiconductors such as CeO2 and V2O5 was reported to achieve high efficiency in catalytic NO removal by NH3. In this paper, we present novel Mn-Ce codoped V2O5/TiO2 catalyst which exhibited an excellent NO conversion efficiency of 90% at 140°C. By using this codoped catalyst, the best low-temperature activity was greatly decreased when compared with single Mn- or Ce-doped catalyst. According to the characterization results from BET, XRD, and XPS, the codoped catalyst was composed of both CeO2 and amorphous Mn. The electron circulation formed between doping elements is believed to promote the electron transfer, which may be one of the reasons for excellent low-temperature denitration performance.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Shangchao Xiong,Jianjun Chen,Nan Huang,Tao Yan,Yue Peng,Junhua Li
The degradation of catalyst properties, rather than the deposition of NH 4 Cl, was the main reason for the deactivation of the MnCe low-temperature SCR (selective catalytic reduction) catalyst under HCl atmosphere. Cl ions prefer to be located at the oxygen vacancies around Mn cations on the MnCe surface. The adsorbed Cl ions could further promote the formation of oxygen vacancies. Therefore, the active Mn sites on the surface of MnCe would be quickly covered by Cl ions when HCl was present and thus promote the formation of Brønsted acid sites. However, the ionic NH 4 + adsorbed on the Brønsted acid sites of MnCe and MnCe − Cl were not fully utilized in the SCR reaction. Meanwhile, the reactivity of the coordinated NH 3 bonded with Lewis acid sites was significantly restrained by HCl due to the significant inhibition of the redox performance. Overall, HCl could obviously restrain the low-temperature SCR activity of MnCe.
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
Engineering
·
2025
·
IF 11.6
Ying Zhu,Jingjing Liu,Guangzhi He,Shaohua Xie,Wenpo Shan,Zhihua Lian,Fudong Liu,Hong He
Catalytic activity and hydrothermal stability are both crucial for the application of the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR catalyst) in diesel vehicles. In this study, a tin (Sn)-modified Ce–Nb mixed-oxide catalyst was synthesized as an NH 3 -SCR catalyst for NO x emission control. After the introduction of Sn, both the NH 3 -SCR activity and the hydrothermal stability of the catalyst were remarkably promoted. Even after hydrothermal aging at 1000 °C, the developed Ce 1 Sn 2 Nb 1 O x catalyst achieved more than 90% NO x conversion at 325–500 °C. Various methods, including N 2 -physisorption, X-ray diffraction, in-situ high-temperature X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption fine-structure spectroscopy, temperature-programmed reduction of hydrogen, temperature-programmed desorption of ammonia, and density functional theory calculations were used to investigate the promotional effects induced by the Sn species. The characterization results showed that the addition of Sn not only promoted the formation of the Ce–Nb active phase but also improved its thermal stability, contributing to the excellent NH 3 -SCR performance and hydrothermal stability. This study provides an excellent sintering-resistance catalyst for the application of diesel engine NO x emission control.
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
CATALYSIS TODAY
·
2016
·
IF 4.312
Xuesong Liu,Xiaodong Wu,Duan Weng,Zhichun Si,Rui Ran
Cu-modified SAPO-34 molecular sieves with different Cu loading amounts were prepared by ion-exchange and impregnation methods. Both series of catalysts were hydrothermally treated at 750 °C in 10 vol% H 2 O/air for 24 h. The catalysts were characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR), NH 3 temperature-programmed desorption (NH 3 -TPD) and diffused reflectance infrared flourier transform spectroscopy (DRIFTS). All the fresh catalysts show high activity toward the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) at low temperatures regardless of preparation method. Generally, the hydrothermal aging shifts the operation window of the catalysts towards high temperatures. The improvement in high-temperatures activity is attributed to the migration of surface CuO clusters into the ion-exchanged sites as isolated Cu 2+ during ageing, which suppresses the competitive oxidation of NH 3 . The loss of low-temperatures activity is also related to the decrease in the amount of active surface CuO clusters, inhibiting the oxidation of NO to NO 2 and fast SCR reaction. Interestingly, the amount of Lewis acid sites increase linearly with the increasing isolated Cu 2+ , while the Brønsted acidity is weakened.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）