RSC Advances
·
2017
·Vol. 7
·期 51
·32146-32154
·
IF 3.108
Chengkai Pang,Yuqun Zhuo,Qiyu Weng
A series of Mn-exchanged SAPO-34 catalysts were synthesized and developed as catalysts for the low temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen. 4Mn/SAPO-34 showed the highest SCR activity in the temperature range of 120–210 °C. The microstructure of zeolite supports, acidity, manganese species and reaction mechanism were investigated in detail by BET, NH3-TPD, UV-Vis, H2-TPR, XPS and in situ DRIFTS. Mn3+ and Mn4+ related species were proved to be the active sites for the SCR reaction. The Eley–Rideal mechanism was proved to be effective on 4Mn/SAPO-34 for the low temperature SCR reaction in which coordinated NH4+ species react with gas-phase NO to form an activated transition state and subsequently decomposed to N2 and H2O.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Ting Yi,Yibo Zhang,Xiangguang Yang
Pt@CeO 2 /MCM-56 (PCM) and CeO 2 -CuO (9:1)/MCM-56 (CCM) were combined to purify the exhaust emissions from diesel vehicles in three configuration statuses, defined as configuration A—where CCM stays above PCM, configuration B—where PCM stays above CCM, and configuration C—where CCM mixes with PCM homogeneously in loose contact. Among these combined catalysts, the configuration A is most favorable for the selective catalytic reduction (SCR) reaction, with >80% NO x conversion obtained at the temperature range of 150–550 °C and gas hourly space velocity (GHSV) of 240,000 ml g −1 h −1 . NH 3 -TPD, H 2- TPR and NH 3 conversion measurements demonstrated that NH 3 can be selectively used to reduce NO x in the configuration A but is over-oxidized if the reaction is operated in configuration B or configuration C status, deteriorating the deNO x activity at temperature above 250 °C. Hence, configuration A not only takes advantage but also overcomes the shortcomings of PCM and CCM, leading to high NO x conversion and N 2 selectivity. A significant decrease in the onset temperature of soot combustion was also observed in this research.
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
APPLIED CLAY SCIENCE
·
2019
·
IF 3.89
Haiyan Yang,Yang Zhou,Dongshen Tong,Miao Yang,Kai Fang,Chunhui Zhou,Weihua Yu
Cellulose is the most abundant form of biomass on earth, and is considered as an alternative for fuels and chemicals. The hydrolysis of cellulose to platform compounds, such as reducing sugars (RS), is one of the most important ways for the utilization of cellulose. In this study, the solid acid catalysts of SO 4 2− -ZrO 2 /montmorillonite (SZ-Mt) were prepared by coupling SO 4 2− with ZrO 2 and then introducing into the interlayer of Mt using the coprecipitation method. Meanwhile, the catalytic performance of the SZ-Mt catalysts for the hydrolysis of cellulose to RS in water was studied. The catalysts were characterized by XRD , FT-IR, BET, SEM(EDS), NH 3 -TPD and XPS . The catalytic results showed that the SZ-Mt composite calcined at 500 °C with the molar ratio of S/Zr of 0.3 showed the highest total reducing sugars yield of 30.1%. The characterization results revealed that the surface S O bonds of sulfated zirconium oxide could gradually change from O=S-OH groups (type I, -HSO 4 ) to O=S=O groups (type II, -S 2 O 7 ). It was concluded that the surface S-OH groups in type I were responsible for the hydrolysis of cellulose in the low molar ratio of S/Zr and the new S-OH bonds formed by breaking the S-O-S bonds in type II were contributed to the conversion of cellulose in the high molar ratio of S/Zr. Finally, the mechanism of cellulose hydrolysis on the SZ composites was suggested.
研究领域:
化学工程
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材料科学
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2017
·Vol. 19
·期 7
·5333-5342
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IF 4.123
Shu-xian Wang,Rui-tang Guo,Wei-guo Pan,Ming-yuan Li,Peng Sun,Shu-ming Liu,Shuai-wei Liu,Xiao Sun,Jian Liu
It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO2 catalyst not only inhibited the adsorption and activation of NH3 species, but also led to the decrease of the activity of adsorbed NH3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O2 over the Ce/TiO2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO2 species did not decrease. Moreover, the results revealed that the NH3-SCR reaction over the Ce/TiO2 catalyst followed both the E–R and L–H mechanisms, while the NH3-SCR reaction over Ce/TiO2-Pb was mainly controlled by the L–H mechanism. The contributions of the L–H mechanism to the SCR reactions over Ce/TiO2 and Ce/TiO2-Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO2-Pb was mainly attributed to the suppressed NH3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites.
研究领域:
环境催化
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大气污染控制
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材料化学
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表面科学
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物理化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 3
·921-930
·
IF 2.936
Zhang Kai,Zhang Huanling,Feng Xipan,Wang Yue,Wang Guowei,Zhu Xiaolin,Li Chunyi
The catalytic activities of metal–based catalysts are largely dependent on the properties of their supports. The support (MgO, Al 2 O 3 , MgAl 2 O 4 , SiO 2, and CeO 2 ) effect of the Sn (1.2 wt%) based catalyst for the ethylbenzene dehydrogenation reaction was firstly investigated. The supported Sn-based catalysts were characterized by NH 3 -TPD, BET, XRD, and H 2 -TPR. Among the tested catalysts, the 1.2 Sn/CeO 2 catalyst presented the most effective catalytic activity, achieving a high ethylbenzene conversion of 56.2 wt% at 600 °C. The obvious support effect should originate from the electronic interaction between Sn and supports, instead of the geometric effect resulting from different dispersion of Sn species on carriers. The high activity of the 1.2 Sn/CeO 2 catalyst was attributed to the generation of oxygen vacancies on the CeO 2 surface. A typical strong metal-support interaction (SMSI) could be found in the 1.2 Sn/CeO 2 catalyst according to the comparison of H 2 -TPR, XPS, and Raman spectra result with pure CeO 2 support. The addition of Sn further promoted the generation of more oxygen vacancies by changing the redox properties of CeO 2 , and inhibited the agglomeration of CeO 2 nanoparticles, thereby enhancing greatly the catalyst's ethylbenzene dehydrogenation activity. Graphical Abstract
研究领域:
催化
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2018
·Vol. 96
·期 12
·2586-2592
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IF 1.265
Renjie Deng,Kuiyi You,Fangfang Zhao,Pingle Liu,He'an Luo
In this work, a simple method for the highly selective preparation of valuable dinitronaphthalene from 1-nitronaphthalene employing NO 2 as a nitrating agent has been developed. The results demonstrated that HY zeolite as an eco-friendly and stable catalyst exhibits good catalytic performances. The total selectivity to valuable dinitronaphthalene compounds including 1,5-, 1,4-, and 1,3-dinitronaphthalene can reach 87.6 % in our present nitration reaction. Meanwhile, the physico-chemical properties of catalysts were characterized by XRD, FTIR, TG/DTG, BET, and NH 3 -TPD, and the probable nitration reaction mechanism was also suggested in this paper. The present nitration process seems to be a mild, eco-friendly, and economical route for the preparation of valuable dinitronaphthalene compounds.
研究领域:
化学工程
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催化
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环境化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2017
·
IF 3.582
Yinghui Sun,Guojie Zhang,Jiwei Liu,Peiyu Zhao,Peng Hou,Ying Xu,Riguang Zhang
CH 4 CO 2 reforming to syngas was investigated over three different activated carbon catalysts. To better understand the influence of the supports on the catalytic properties , catalysts were analyzed by some characterization methods, such as nitrogen adsorption–desorption isotherms, XRD , H 2 -TPR, NH 3 -TPD, CO 2 -TPD, FTIR, TEM and EDX . The results showed that the catalyst with AC 2 as the support provided the best catalytic activity . The CH 4 conversion and CO 2 conversion were 92% and 98% at 900 °C, respectively; best selectivity with the H 2 /CO ratio was close to 1 among the three supports used. It also showed a better stability at 900 °C. H 2 -TPR analysis showed that Co species in Co/AC 2 catalyst were strong interaction with the support. It was observed that active metals were well dispersed on the AC 2 support by the TEM. In addition, the ratio of CH 4 /CO 2 also had great influence on the CH 4 and CO 2 conversion.
研究领域:
催化
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Chemistry & Engineering
·
2022
·Vol. 8
·期 1
·64-76
·
IF 5.2
Haosheng Xin,Haiyong Wang,Xiaohong Hu,Xiuzheng Zhuang,Long Yan,Chenguang Wang,Longlong Ma,Qiying Liu
Cellulose hydrolysis and further conversion to diketones and alcohols was performed with graphene layer encapsulated cobalt catalysts (Co@C) in phosphoric acid aqueous solution. A total of 60.5% yield of the products mainly including ethanol, 2,5-hexanedione (2,5-HD) and diols could be achieved in 0.06 M H3PO4 solution. A series of characterization methods such as XRD, XPS, TEM, TG-MS, BET, ICP, H2-TPD, NH3-TPD, and Raman were carried out to explore the catalyst formation mechanism and reaction activity. The results of the analysis indicated that the calcination temperature had a deep influence on the structure formation of the Co@C catalysts, thus leading to differences in the reaction activity. While the calcination temperature was determined at 700 °C, the Co@C catalyst meets with the requirements of optimal reaction activity, appropriate particle size, suitable surface area, and pore size. Besides, it was found that H3PO4 is not only favorable in cellulose hydrolysis but also cooperates with the Co@C catalyst in the hydrogenolysis of C–O bond and C–C bonds for the formation of products. This work provides a possible way for renewable cellulose conversion to diketone and alcohols over encapsulated non-noble metal catalyst combined with phosphoric acid aqueous solution.
研究领域:
化学工程
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催化
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiaojun Dai,Yan Cheng,Meng Si,Qiang Wei,Dongdong Chen,Wenbin Huang,Yasong Zhou
A series of SAPO-11 molecular sieves were synthesized in the concentrated gel system by reducing the water content in the synthesis system. With SAPO-11 molecular sieves as supports, NiW-supported catalysts were prepared for the hydroisomerization of n-hexadecane. SAPO-11 molecular sieves and catalysts were characterized by XRD, SEM, N 2 adsorption–desorption, NH 3 -TPD, Py-IR, HRTEM and XPS. The results showed that reducing the water content in the synthesis system could increase the mesoporous volume of SAPO-11 molecular sieve and improve the acidity of SAPO-11. For the corresponding catalysts, using SAPO-11 synthesized in concentrated gel system as the support weakened the interaction between the active phase and the support, and increased the dispersion and stacking number of the active phase, which effectively improved the catalytic performance of the catalyst. The yield of i-hexadecane of the catalyst NiW/45W-SA corresponding to SAPO-11 synthesized in conventional water content system was 28.14%, while that of the catalyst NiW/5W-SA corresponding to SAPO-11 synthesized in concentrated gel system was 52.24%. According to the distribution of isomers, it is inferred that hydroisomerization of n-hexadecane over NiW/SAPO-11 follows the pore-mouth mechanism.
研究领域:
催化
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材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2022
·
IF 4.05
Xiao Yaoxin,Zhang Jun,Zhu Lingjun,Shan Rui,Yuan Haoran,Chen Yong
A series of inexpensive electroplating sludge-derived magnetic copper-containing catalysts were developed for the selective hydrogenation of biomass-based furfural (FFR) into furfuryl alcohol (FA) and 2-methylfuran (MF). The specific structural characteristics of as-prepared magnetic copper-containing samples were clearly identified through various techniques, including XRD, XPS, N 2 adsorption–desorption, NH 3 -TPD, SEM and so on. The characterizations revealed that the hydrogen pre-activated magnetic catalysts supplied metallic Cu species, medium acidity and porosity for the catalytic upgrading of FFR in hydrogen atmosphere. As for FFR-to-FA as well as FFR-to-MF transformations, the magnetic copper-containing catalyst with calcination temperature of 800 °C exhibited excellent performance towards the formation of FA and MF, wherein desirable FA yield of 98.5 mol% and MF yield of 71.3 mol% were achieved at reaction temperatures of 160 °C and 240 °C, respectively. The reuse experiments indicated that the recycled catalysts still maintained excellent activity and stability even after four-time recycling. The present study thus highlights a new approach for the resource utilization of electroplating sludge, which also supplies low-cost and efficient catalytic materials for the selective upgrading of various biomass-derived platform molecules.
研究领域:
催化
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化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Chenxi Lu,Yuanzhuo Zhou,Liangzhi Li,Hongwei Chen,Lishi Yan
Catalytic production of 5-hydroxymethylfurfural (5-HMF) from glucose is a promising routine for generation of varied value-added chemicals. Herein, Mixed-Metal metal–organic frameworks (MOFs)–Fe/MIL-101(Cr) and MIL-101(Cr, Fe) obtained from post-synthesis modification and one-pot synthesis approach respectively were applied for catalytic converting glucose to 5-HMF. The synthesized Mixed-Metal MOFs were characterized by PXRD, SEM, N 2 adsorption–desorption analysis, TGA, XPS and NH 3 -TPD. Cr-and Fe-containing Mixed-Metal MOFs Fe/MIL-101(Cr) and MIL-101(Cr, Fe) presented synergistic effect with enhanced catalytic ability for glucose transformation to 5-HMF compared with typical single-metal MOFs and sulfonic acid-functionalized MOFs. Moreover, these two Mixed-Metal MOFs also presented better thermal stability than single-metal MOFs like MIL-101(Cr). Fe/MIL-101(Cr) was found to possess higher catalytic performance than MIL-101(Cr, Fe). 55.8 % 5-HMF yield was obtained with Fe/MIL-101(Cr) at 170 °C for 2 h in DMSO/water system. In addition, Fe/MIL-101(Cr) demonstrated desired recyclability for five times without incredible loss in its activity. This study provides a Mixed-Metal strategy on MOFs for improving catalytic efficiency of glucose conversion to 5-HMF.
研究领域:
化学工程
·
材料科学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Shiwei Feng,Chengping Zhang,Hengdao Quan
As an environmentally friendly cleaning agent, Z -1-chloro-3,3,3-trifluoropropene (HCFO-1233zd( Z )) can realize industrial production by the isomerization of HCFO-1233zd( E ). Herein, various isomerization catalysts with different structures, compositions and acid properties were prepared through the fluorination of γ-Al 2 O 3 with CHF 3 by controlling the activation conditions. For the first time, the catalysts for HCFO-1233zd( E ) isomerization were systematically studied by XRD, N 2 physisorption, XPS, SEM, MAS NMR spectroscopy, NH 3 -TPD and py-IR. The active site of this reaction was revealed and the catalyst deactivation mechanism was proposed. It turned out that HCFO-1233zd( E ) isomerization prefers to occur at Lewis acid sites with moderate density and strength. The amorphous particles composed of γ-Al 2 O 3 , Al 2 O 3 (F) and α-AlF 3 ( R 3 ¯ c ) at 450 °C exhibit highly catalytic activity for HCFO-1233zd( E ) isomerization. After 100 h evaluation, it was found that residual γ-Al 2 O 3 can be fluorinated by HCFO-1233zd( E ) to form needle-like structures which could induce the amorphous Al 2 O 3 (F) particles to reorganize and give cubic structures, where the Lewis acid properties were enhanced, leading to catalyst deactivation.
研究领域:
催化
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化学工程
·
材料科学
·
环境化学
✓ 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）