JOURNAL OF CATALYSIS
·
2021
·
IF 7.92
Yonglong Li,Senyou Yang,Honggen Peng,Wenming Liu,Yangyang Mi,Zheng Wang,Changjin Tang,Daishe Wu,Taicheng An
Manganese (Mn)-based mixed oxides are considered the most efficient catalysts for low-temperature ammonia selective catalytic reduction of nitrogen oxides (NO x ) (NH 3 -SCR of NO x ). Water resistance and sulfur tolerance, especially the SO 2 tolerance of Mn-based catalysts, are the main obstacles preventing their practical application. Therefore, in this study, a series of cobalt (Co)-doped MnFeO x ternary mixed oxides catalysts with a hierarchically ordered structure (Hierc-MnFe 1-δ Co δ O x , δ = 0.2, 0.4 and 0.6) were developed and applied for NH 3 -SCR of NO x at low temperature. Compared with Hierc-MnFeO x , Hierc-MnFe 1-δ Co δ O x catalyst exhibited enhanced low-temperature activity and a broadened temperature window (NO x conversion above 80% was between 90 and 343 °C over Hierc-MnFe 0.6 Co 0.4 O x ), as well as better H 2 O resistance and SO 2 tolerance. The enhanced low-temperature activity was attributed to a larger amount of active oxygen species, a higher proportion of Mn 4+ , Fe 3+ and Co 3+ content, and the improvement of surface acidity, which can facilitate the adsorption and activation of NO and NH 3 . Additionally, the Hierc-MnFe 0.6 Co 0.4 O x catalyst exhibited superior soot tolerance due to its special hierarchically ordered architecture. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that the Co-modified Hierc-MnFe 1-δ Co δ O x ternary oxide catalyst could efficiently protect nitrate species on Hierc-MnFe 0.6 Co 0.4 O x from the poisoning effect of SO 2 , thereby boosting its SO 2 tolerance. This study provides a good candidate for low-temperature de NO x application with enhanced SO 2 and soot tolerance.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Zulfiqar Ali,Yang-wen Wu,Yue Wu,Zulqarnain Arain,Ming-xin Xu,Qiang Lu,Heping Ma,Huan-yu Zhao
Lead (Pb) species are inescapable constituents of the flue gas from coal-fired power plants and other thermal devices, which can cause impeding effects on the selective catalytic reduction (SCR) reactions. Here, the poisoning effects of Pb on the V 2 O 5 -MoO 3 /TiO 2 type SCR catalyst were examined. The poisoned catalysts were prepared by the solid diffusion and incipient wetness impregnation (IWI) methods. The catalytic activity tests indicated that the Pb-doped catalyst prepared by the IWI method suffered a considerable drop in catalytic activity, while a slender influence was observed on the Pb-loaded catalysts prepared by solid diffusion method. Comprehensive characterizations and density functional theory (DFT) calculations were performed on the fresh and poisoned catalysts prepared by the IWI method to unveil the deactivation mechanism. The results showed that Pb species covered the active sites (V species) on the catalyst surface, resulted in the decrease in chemisorbed oxygen, hence reducing the surface acidities. The decrease in reducibility of the catalyst was an important factor for poisoning of the catalyst. Moreover, Pb species reacted with MoO 3 to form PbMoO 4 which agglomerated on the catalyst surface to further deactivate the catalyst.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Yonglong Li,Wenming Liu,Ran Yan,Jian Liang,Tao Dong,Yangyang Mi,Peng Wu,Zheng Wang,Honggen Peng,Taicheng An
A series of hierarchical three-dimensionally ordered macroporous Fe 10-x V x binary metal oxides (3DOM-Fe 10-x V x ) catalysts were designed and synthesized for selective catalytic reduction of NO x from marine diesel engine exhaust. The physical-chemical performance of the 3DOM-Fe 10-x V x catalysts were subjected by various techniques and found that the 3DOM-Fe 10-x V x with the Fe to V atomic ratio of 9.0/1.0 exhibited a wider active temperature window, better soot resistance performance compared with the conventional Fe 9.0 V 1.0 catalyst due to its special 3DOM structure. Even when simultaneously exposed to the soot and high concentration of sulfur dioxide reaction feeds, the 3DOM-Fe 9.0 V 1.0 catalyst also displayed superior catalytic activity. Interestingly, we found that the soot had a reduction activity for NO x at high reaction temperature, which can effectively extend its active temperature window. The 3DOM-Fe 10-x V x catalysts prepared in this work could be potentially a good candidate for the cargo ships de NO x catalysts to satisfy the more stringent exhaust emission rules.
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Jianping Ding,Xiaoyan Zhou,Zhengzheng Yang,Changgeng Liu,Mingchao Sun,Congling Yang,Lu Fan
In this study, a novel strategy was proposed for synthesizing dual single-atom Ce-Ti catalysts supported on γ-Fe 2 O 3 via ball milling and calcination. Compared to γ-Fe 2 O 3 and single-atom Ce/γ-Fe 2 O 3 and Ti/γ-Fe 2 O 3 catalysts, the Ce-Ti/γ-Fe 2 O 3 catalyst exhibits superior NO conversion rates and significantly enhanced tolerance to H 2 O and SO 2 at 200–240 °C. These advancements are attributed to the synergistic interactions between Ce and Ti, which enhance redox properties, increase Lewis acid site density, and facilitate the Langmuir-Hinshelwood reaction pathway. In-situ DRIFTS and density functional theory (DFT) analyses revealed the mechanistic role of surface-active oxygen species and intermediate formation in promoting the SCR reaction. The findings provide valuable mechanistic insights and establish a scalable approach for the development of high-performance, environmentally friendly catalysts for industrial NO x removal.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Pengkai Jin,Liu Yang,Zhongyi Sheng,Xinyue Chu,Dianhui Chen
An indium and copper-doped mordenite catalyst (InCu/MOR) was prepared and tested as a potential catalyst for high temperature NH 3 selective catalytic reduction (NH 3 -SCR) of NO x in the gas turbine . The InCu/MOR catalyst exhibited excellent catalytic activity (over 83 % NO x conversion) in the presence of 5 % H 2 O and 100 ppm SO 2 above 550 °C. A series of characterization (XRD, Py-TR, XPS, NH 3 -TPD, H 2 -TPR and in-situ DRIFTS) were applied to analyze the catalyst. The obtained results showed that the addition of indium promoted the formation of isolated Cu 2+ and more Brønsted acid sites, which could improve the tolerance to sulfur dioxide and inhibit the occurrence of high temperature ammonia oxidation side reactions. Meanwhile, the ammonia on InO + /In 2 O 3 sites was activated and reacted with the nitrate/nitrite species on the catalyst surface to form nitroammonium (NH 4 NO 3 /NH 4 NO 2 ), which was a short lived intermediate for NH 3 -SCR. The superior catalytic performance of InCu/MOR could attribute to these comprehensive effects.
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 97
·期 10
·2834-2843
·
IF 3.709
Yue Cao,Boyuan Chen,Yongli Dong,Yujun Zhu,Zhibin Li
BACKGROUND A series of Cu-SAPO-34 samples were prepared with different copper sources and addition of tetraethylenepentamine (TEPA) by a one-pot method, which were applied for selective catalytic reduction of NO x with ammonia (NH 3 -SCR). RESULTS Various measurements were carried out to investigate the effect of TEPA addition and copper sources used on sample properties. The results indicated that Cu-SAPO-34 obtained with the addition of TEPA using copper citrate (Cu-SAPO-34-TC) displayed over 90% NO x conversion at 150–500 °C and excellent H 2 O and SO 2 resistance in NH 3 -SCR. This is because the addition of TEPA can control the formation of isolated Cu 2+ species located at the junction of D6R in CHA cage, Site (I), which is regarded as a more easily approachable site to adsorbates (NH 3 and NO) than others, thus leading to the excellent NH 3 -SCR performance. Further study demonstrated that the Cu-SAPO-34-TC catalyst shows much wider temperature window and more hydrothermal stability due to a greater amount of surface isolated Cu 2+ , fewer Si islands and more Al(IV) species. CONCLUSIONS The excellent activity of the Cu-SAPO-34-TC catalyst can be attributed to the addition of TEPA, which is beneficial for controlling the isolated Cu 2+ at Site (I) as well as inhibiting the aggregation of CuO species. Various characterizations also confirm that more surface Cu 2+ can be produced using copper citrate as copper source. © 2022 Society of Chemical Industry (SCI).
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 47
·71721-71730
·
IF 5.19
Huang Wenjun,Li Sichao,Wang Hongbin,Cui Peng,Xu Haomiao,Cheng Can,Qu Zan,Yan Naiqiang
Oxidation–reduction-absorption based on sulfite is a promising process for simultaneous removal of NO x and SO 2 . However, excessive oxidation of sulfite and competitive absorption between NO x and SO 2 limit its application. A matching strategy between antioxidants and alkaline agents has been proposed to solve these problems and enhance the absorption process. The comparison results of inhibitors showed that hydroquinone exhibited long-term high-efficiency inhibition of S(IV) (SO 3 2- /HSO 3 - ) oxidation. The comparison of alkaline agents showed that the Na 2 SO 3 solution with heterogeneous mixture of MgO and hydroquinone exhibited better absorption performance than that with other combinations. The absorption amounts of NO x in 0.15 mol/L Na 2 SO 3 50 mL solution added 0.1% hydroquinone (HQ) with 0.09 mol/L MgO were 2.24 mmol, which improved 5 times than that without additives. In addition, studies on the influence of pH showed that the pH of MgO mixture could be stabilized at 9–10 for a long time, while the pH of Na 2 CO 3 mixture decreased faster. Further studies suggested that the hydration of MgO resulted in the solution with MgO keeping high pH. This is also the main reason why the combination of MgO and hydroquinone is superior to the combination of Na 2 CO 3 and hydroquinone in desulfurization and denitration performance.
✓ 已验证
产品关联
DOI
PubMed
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.
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yu Zhang,Rui Wang
NH 3 ‑selective catalytic reduction as the fascinating technology for complete NO x removal, the key in practical applications is to explore advanced catalysts with high catalytic reactivity and stability at low temperature. Herein, a series of hollow spherical AMnO x (A = Ce, Cu, Ni) catalysts was fabricated by using carbon nanospheres as sacrificial template. Characterization analysis including XRD, ICP, BET, SEM, TEM, H 2 -TPR, NH 3 -TPD, XPS, in situ DRIFTS together with kinetic studies were applied to acquire knowledge of the morphological structure and surface features of the catalysts as-prepared. We also performed a comparative study on three samples with regard to their SCR activity at low temperatures. Notable, the catalytic activity of the NiMnO x catalyst (95.9 %) was vastly superior to that of the CeMnO x (85.4 %) and CuMnO x (30.5 %) at 100 °C. This enhanced low-temperature activity of NiMnO x are correlated against hollow structure with more active sites, wider pore distribution, higher surface Mn content and the enhancement in surface acidity and reducibility. Even with 5 vol% H 2 O in the reaction gas fraction, the catalytic performance of NiMnO x hollow spheres was superior to the other two catalysts. Besides, it can be used for six consecutive runs without suffering a substantial activity loss. Additionally, the impact of various crucial process variables, including space velocity, H 2 O, SO 2 , and metal poisons, on the denitrification efficiency of NH 3 -SCR was examined. The current researches have a positive guiding role in the development of high-efficiency low-temperature NH 3 -SCR denitrification catalysts to boost NO x degradation.
✓ 已验证
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 12
·4149
·
IF 3.748
Yinghui Wang,Xiurong Guo,Danfeng Du,Shaochi Yang
Perovskite-type catalysts were widely used in the field of automobile exhaust purification due to their inherent physicochemical properties and excellent doping characteristics. A series of La1−xMxCo1−yNyO3(M = Ce, Ca; N = Fe, Mn) perovskite-type catalyst samples were prepared by sol-gel method for the four-way purification of PM, NOx, CO, and HC emitted by diesel exhaust. The activity of catalyst samples was tested by simulation experiments and hydrogen temperature-programmed reduction (H2-TPR). Catalyst samples were characterized by means of XRD, FT-IR, SEM, BET, and XPS analysis. The results demonstrated that the perovskite-type catalyst samples with a particle pore size of 3–5 μm can be prepared by sol-gel method. When A-site of LaCoO3perovskite-type oxide was doped by cerium ions, the catalyst samples produced small distortion. The doping of cerium ions to A-site was more conducive to the four-way purification of diesel exhaust than calcium ions. La0.8Ce0.2CoO3perovskite-type samples showed the best purification efficiency, and the purification efficiencies of PM, NOx, CO, and HC were 90%, 85%, 94%, and 100%, respectively. When the B-site of La0.8Ce0.2CoO3perovskite was doped with iron ions, the purification efficiency of catalyst samples for PM and NOxcan be further enhanced. When the B-site of La0.8Ce0.2CoO3perovskite was doped with manganese ions, the purification efficiency of the catalyst samples for PM can be further enhanced. It can be seen from the simulation experiments that La0.8Ce0.2Co0.7Fe0.3O3perovskite was the best doping amount, and the purification efficiencies of PM, NOx, CO, and HC were 95%, 92%, 94%, and 100%, respectively.Keywords:perovskite-type catalyst;diesel exhaust;sol-gel method;four-way purification;doping amount
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Mianxing Luo,Meng Zhang,Changbiao Chi,Guo Chen
It is of great significance to study the effect of multi-enzyme aggregation behavior at the interface on the formation of multi-enzyme complexes and their co-catalytic characteristics, which is helpful for us to design and construct immobilized multi-enzyme complex systems for in vitro synthetic biology. Here, a magnetic microsphere with chelated Ni 2+ , was prepared to explore the self-assembly characteristics of PduQ-SpyTag (P-T) and Nox-SpyCatcher (N C) on its surface, based on the mixed interaction mode consisting the affinity of His-tag/Ni 2+ and covalent binding of SpyTag/SpyCatcher. After studying the effect of saturated or unsaturated adsorption of P-T on the covalent binding between P-T and N C at the interface, a possible multienzyme interaction mechanism for the affinity-assisted covalent self-assembly on the Ni 2+ chelating surface was proposed. The time evolution of NADH showed that the immobilized P-T/N-C complex formed by this method and the free P-T/N-C complex exhibited similar synergistic catalytic properties, and presented higher catalytic efficiency than the simple mixing of P-T and N C. The optimal catalytic conditions, stability and reusability of the immobilized multi-enzyme complexes prepared in this study were also discussed by comparing them with free enzymes. In this study, we demonstrate a simple and effective strategy for self-assembling SpyTag/SpyCatcher fusion proteins on the surface of magnetic beads, which is inspiring for the construction of more cascade enzyme systems at the interface. It provides a new method for facilitating the rapid construction of immobilized multi-enzyme complexes in vitro from the crude cell lysis .
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2020
·
IF 3.687
Yiqing Zeng,Zihua Wu,Lina Guo,Yanan Wang,Shule Zhang,Qin Zhong
The problems of easily inactivated by SO 2 poisoning and high N 2 O formation for MnO x based catalysts hinder its application in selective catalytic reduction (SCR) of NO x with NH 3 . The SO 2 poisoning mechanism has been well demonstrated, but the N 2 O formation mechanism was still controversial due to previous limited study. Herein, MnO 2 supported on MO x (Mn/M, M = Al, Si and Ti) were prepared by wet impregnation method to investigate the carrier effect on the formation of N 2 O. Although all of selected supports had a large amount of surface acid sites, only forming strong active-support interaction can separate the activation sites of NH 3 and NO + O 2 . Accordingly, the activation of NH 3 and NO + O 2 on MnTi was respectively occurred on TiO 2 and MnO 2 , but both NH 3 and NO + O 2 was activated on MnO 2 over MnAl and MnSi samples. The over-activation (NH 2 dissociated into NH) of NH 3 would be effectively inhibited when NH 3 activation was occurred on TiO 2 , thus it can significantly suppress the formation of N 2 O. In contrast, the NH 3 species would sharply decompose into NH on MnO 2 and then lead to the high amount of N 2 O. Finally, we proposed some methods that might effectively improve the selectivity of MnO x- based catalysts.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）