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Effect of Cu-ZSM-5 catalysts with different CuO particle size on selective catalytic oxidation of N,N-Dimethylformamide

《环境科学与工程前沿(英文)》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1557-0

摘要:

● A series of Cu-ZSM-5 catalysts were tested for DMF selective catalytic oxidation.

关键词: N     N-Dimethylformamide     Selective catalytic oxidation     Cu-ZSM-5     CuO particle size    

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selectivecatalytic oxidation of cyclohexane

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1211-1223 doi: 10.1007/s11705-022-2145-3

摘要: The one-step highly selective oxidation of cyclohexane into cyclohexanone and cyclohexanol as the essential intermediates of nylon-6 and nylon-66 is considerably challenging. Therefore, an efficient and low-cost catalyst must be urgently developed to improve the efficiency of this process. In this study, a Co3O4–CeO2 composite oxide catalyst was successfully prepared through ultrasound-assisted co-precipitation. This catalyst exhibited a higher selectivity to KA-oil, which was benefited from the synergistic effects between Co3+/Co2+ and Ce4+/Ce3+ redox pairs, than bulk CeO2 and/or Co3O4. Under the optimum reaction conditions, 89.6% selectivity to KA-oil with a cyclohexane conversion of 5.8% was achieved over Co3O4–CeO2. Its catalytic performance remained unchanged after five runs. Using the synergistic effects between the redox pairs of different transition metals, this study provides a feasible strategy to design high-performance catalysts for the selective oxidation of alkanes.

关键词: Co3O4–CeO2 composite oxides     cyclohexanone     cyclohexanol     ultrasonic-assisted co-precipitation     selective oxidation     solvent-free    

Multi-stage ammonia production for sorption selective catalytic reduction of NO

Chen ZHANG, Guoliang AN, Liwei WANG, Shaofei WU

《能源前沿(英文)》 2022年 第16卷 第5期   页码 840-851 doi: 10.1007/s11708-021-0797-1

摘要: Sorption selective catalytic reduction of nitrogen oxides (NOx) (sorption-SCR) has ever been proposed for replacing commercial urea selective catalytic reduction of NOx (urea-SCR), while only the single-stage sorption cycle is hitherto adopted for sorption-SCR. Herein, various multi-stage ammonia production cycles is built to solve the problem of relative high starting temperature with ammonia transfer (AT) unit and help detect the remaining ammonia in ammonia storage and delivery system (ASDS) with ammonia warning (AW) unit. Except for the single-stage ammonia production cycle with MnCl2, other sorption-SCR strategies all present overwhelming advantages over urea-SCR considering the much higher NOx conversion driven by the heat source lower than 100°C and better matching characteristics with low-temperature catalysts. Furthermore, the required mass of sorbent for each type of sorption-SCR is less than half of the mass of AdBlue for urea-SCR. Therefore, the multifunctional multi-stage sorption-SCR can realize compact and renewable ammonia storage and delivery with low thermal energy consumption and high NOx conversion, which brings a bright potential for efficient commercial de-NOx technology.

关键词: selective catalytic reduction (SCR)     nitrogen oxides (NOx)     ammonia     composite sorbent     chemisorption    

Effects of support acidity on the reaction mechanisms of selective catalytic reduction of NO by CH

Shicheng XU, Junhua LI, Dong YANG, Jiming HAO

《环境科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 186-193 doi: 10.1007/s11783-009-0016-5

摘要: The reaction mechanisms of selective catalytic reduction (SCR) of nitric oxide (NO) by methane (CH ) over solid superacid-based catalysts were proposed and testified by DRIFTS studies on transient reaction as well as by kinetic models. Catalysts derived from different supports would lead to different reaction pathways, and the acidity of solid superacid played an important role in determining the reaction mechanisms and the catalytic activities. Higher ratios of Br?nsted acid sites to Lewis acid sites would lead to stronger oxidation of methane and then could facilitate the step of methane activation. Strong Br?nsted acid sites would not necessarily lead to better catalytic performance, however, since the active surface NO species and the corresponding reaction routes were determined by the overall acidity strength of the support. The reaction routes where NO moiety was engaged as an important intermediate involved moderate oxidation of methane, the rate of which could determine the overall activity. The reaction involving NO moiety was likely to be determined by the step of reduction of NO. Therefore, to enhance the SCR activity of solid superacid catalysts, reactions between appropriate couples of active NO species and activated hydrocarbon intermediates should be realized by modification of the support acidity.

关键词: selective catalytic reduction (SCR)     nitric oxide (NO)     methane     support acidity     Br?nsted acid sites     NOy species    

Transition metal-doped heteropoly catalysts for the selective oxidation of methacrolein to methacrylic

Yanxia Zheng,Heng Zhang,Lei Wang,Suojiang Zhang,Shaojun Wang

《化学科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 139-146 doi: 10.1007/s11705-015-1548-9

摘要: Heteropoly compounds with the general formula Cs M H P Mo VO (M= Fe, Co, Ni, Cu or Zn) and Cs Cu H P Mo VO ( = 0.1, 0.3 or 0.7) were synthesized and then used as catalysts for the selective oxidation of methacrolein to methacrylic acid. The effects of the transition metals on the structure and activity of the catalysts were investigated. FTIR spectra showed that the transition metal-doped catalysts maintained the Keggin structure of the undoped catalysts. X-ray diffraction results indicated that before calcination, the catalysts doped with Fe and Cu had cubic secondary structures, while the catalysts doped with Co, Ni or Zn had both triclinic and cubic phases and the Co-doped catalyst had the highest content of the triclinic form. Thermal treatment can decrease the content of the triclinic phase. NH temperature-programmed desorption and H temperature-programmed reduction results showed that the transition metals changed the acid and redox properties of the catalysts. The addition of Fe or Cu had positive effects on the activities of the catalyst which is due to the improvement of the electron transfer between the Fe or Cu and the Mo. The effects of the copper content on structure and catalytic activity were also investigated. The Cs Cu H P Mo VO catalyst had the best performance for the selective oxidation of methacrolein to methacrylic acid.

关键词: heteropoly compounds     transition metals     selective oxidation     methacrolein    

Effect of different acid anions on highly efficient Ce-based catalysts for selective catalytic reduction

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1399-1411 doi: 10.1007/s11705-023-2345-5

摘要: Three kinds of Ce-based catalysts (CePO4, CeVO4, Ce2(SO4)3) were synthesized and used for the selective catalytic reduction (SCR) of NO by NH3. NH3-SCR performances were conducted in the temperature range of 80 to 400 °C. The catalytic efficiencies of the three catalysts are as follow: CePO4 > CeVO4 > Ce2(SO4)3, which is in agreement with their abilities of NH3 adsorption capacities. The highest NO conversion rate of CePO4 could reach about 95%, and the catalyst had more than 90% NO conversion rate between 260 and 320 °C. The effect of PO43–, VO43– and SO42– on NH3-SCR performances of Ce-based catalysts was systematically investigated by the X-ray photoelectron spectroscopy analysis, NH3 temperature programmed desorption, H2 temperature programmed reduction and field emission scanning electron microscopy tests. The key factors that can enhance the SCR are the existence of Ce4+, large NH3 adsorption capacity, high and early H2 consumptions, and suitable microstructures for gas adsorption. Finally, CePO4 and CeVO4 catalysts also exhibited relatively strong tolerance of SO2, and the upward trend about 8% was detected due to the sulfation enhancement by SO2 for Ce2(SO4)3.

关键词: CePO4     CeVO4     Ce2(SO4)3     selective catalytic reduction     NO removal    

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selectivecatalytic reduction of NO

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1337-7

摘要:

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst.

关键词: NOx     Selective catalytic reduction     Iron-based catalyst     Red mud     Monolithic catalyst     Activated carbon    

Microwave-assisted catalytic oxidation of gaseous toluene with a Cu-Mn-Ce/cordierite honeycomb catalyst

Longli Bo, Shaoyuan Sun

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 385-392 doi: 10.1007/s11705-018-1738-3

摘要: A novel Cu-Mn-Ce/cordierite honeycomb catalyst was prepared by an incipient wetness method and the catalyst was characterized. The active ingredients were present as various spinel species of Cu, Mn and Ce oxides with different valences and they were unevenly dispersed over the surface of the catalyst. The catalytic oxidation of gaseous toluene was primarily investigated using a fixed bed reactor under microwave heating in the continuous flow mode. Under the optimal conditions of 6.7 wt-% loading of the active component, a bed temperature of 200°C, a flow rate of 0.12 m ·h and an initial concentration of toluene of 1000 mg·m , the removal and mineralization efficiencies of toluene were 98% and 70%, respectively. Thus the use of the microwave effectively improved the oxidation of toluene and this is attributed to dipole polarization and hotspot effects. After four consecutive cycles (a total of 1980 min), the Cu-Mn-Ce/cordierite catalyst still exhibited excellent catalytic activity and structural stability, and the toluene removal was higher than 90%. This work demonstrates the possibility of treating volatile organic compounds in exhaust gases by microwave-assisted catalytic oxidation.

关键词: microwave     catalytic oxidation     toluene     Cu-Mn-Ce/cordierite     mineralization    

Design and operational considerations for selective catalytic reduction technologies at coal-fired boilers

Jeremy J. SCHREIFELS, Shuxiao WANG, Jiming HAO

《能源前沿(英文)》 2012年 第6卷 第1期   页码 98-105 doi: 10.1007/s11708-012-0171-4

摘要: By the end of 2010, China had approximately 650 GW of coal-fired electric generating capacity producing almost 75% of the country’s total electricity generation. As a result of the heavy reliance on coal for electricity generation, emissions of air pollutants, such as nitrogen oxides (NO ), are increasing. To address these growing emissions, the Ministry of Environmental Protection (MEP) has introduced new NO emission control policies to encourage the installation of selective catalytic reduction (SCR) technologies on a large number of coal-fired electric power plants. There is, however, limited experience with SCR in China. It is therefore useful to explore the lessons from the use of SCR technologies in other countries. This paper provides an overview of SCR technology performance at coal-fired electric power plants demonstrating emission removal rates between 65% and 92%. It also reviews the design and operational challenges that, if not addressed, can reduce the reliability, performance, and cost-effectiveness of SCR technologies. These challenges include heterogeneous flue gas conditions, catalyst degradation, ammonia slip, sulfur trioxide (SO ) formation, and fouling and corrosion of plant equipment. As China and the rest of the world work to reduce greenhouse gas emissions, carbon dioxide (CO ) emissions from parasitic load and urea-to-ammonia conversion may also become more important. If these challenges are properly addressed, SCR can reliably and effectively remove up to 90% of NO emissions at coal-fired power plants.

关键词: nitrogen oxides (NOx)     coal     selective catalytic reduction (SCR)     air pollution control    

Catalytic oxidation of

Na Li, Xin Xing, Yonggang Sun, Jie Cheng, Gang Wang, Zhongshen Zhang, Zhengping Hao

《环境科学与工程前沿(英文)》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1284-3

摘要: Abstract • Superior catalytic activity observed for o-chlorophenol oxidation on Co2MgAlO. • The reducibility, oxygen species and basicity influenced catalytic activity. • The organic by-products were generated in o-chlorophenol catalytic oxidation. A cobalt-based hydrotalcite-like compound was prepared using a constant-pH coprecipitation method. Cobalt-transition metal oxides (Co2XAlO, X= Co, Mg, Ca and Ni) were investigated for the deep catalytic oxidation of o-chlorophenol as a typical heteroatom contaminant containing chlorine atoms. The partial substitution of Co by Mg, Ca or Ni in the mixed oxide can promote the catalytic oxidation of o-chlorophenol. The Co2MgAlO catalyst presented the best catalytic activity, and could maintain 90% o-chlorophenol conversion at 167.1°C, compared only 27% conversion for the Co3AlO catalyst. The results demonstrated that the high activity could be attributed to its increased low-temperature reducibility, rich active oxygen species and excellent oxygen mobility. In the existence of acid and base sites, catalysts with strong basicity also showed preferred activity. The organic by-products generated during the o-chlorophenol catalytic oxidation over Co2MgAlO catalyst included carbon tetrachloride, trichloroethylene, 2,4-dichlorophenol, and 2,6-dichloro-p-benzoquinon, et al. This work provides a facile method for the preparation of Co-based composite oxide catalysts, which represent promising candidates for typical chlorinated and oxygenated volatile organic compounds.

关键词: Hydrotalcite-derived mixed oxides     o-chlorophenol     Catalytic oxidation     Organic by-products    

Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selectivecatalytic reduction of NO with NH

Minhua Zhang, Baojuan Huang, Haoxi Jiang, Yifei Chen

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 594-602 doi: 10.1007/s11705-017-1668-5

摘要: A mild deposition method was used to fabricate Mn-based catalysts on a UiO-66 carrier for the selective catalytic reduction of NO by NH (NH -SCR). The catalyst with 8.5 wt-% MnO loading had the highest catalytic activity for NH -SCR with a wide temperature window (100–290 °C) for 90% NO conversion. Characterization of the prepared MnO /UiO-66 catalysts showed that the catalysts had the crystal structure and porosity of the UiO-66 carrier and that the manganese particles were well-distributed on the surface of the catalyst. X-ray photoelectron spectroscopy analysis showed that there are strong interactions between the MnO and the Zr oxide secondary building units of the UiO-66 which has a positive effect on the catalytic activity. The 8.5 wt-% MnO catalyst maintained excellent activity during a 24-h stability test and exhibited good resistance to SO poisoning.

关键词: metal-organic framework     selective catalytic reduction     manganese oxides     deNOx     SO2 resistance    

Low-temperature selective catalytic reduction of NO with NH based on MnO-CeO/ACFN

SHEN Boxiong, LIU Ting, SHI Zhanliang, SHI Jianwei, YANG Tingting, ZHAO Ning

《化学科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 325-329 doi: 10.1007/s11705-008-0053-9

摘要: MnO-CeO/ACFN were prepared by the impregnation method and used as catalyst for selective catalytic reduction of NO with NH at 80°C–150°C. The catalyst was characterized by N-BET, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The fraction of the mesopore and the oxygen functional groups on the surface of activated carbon fiber (ACF) increased after the treatment with nitric acid, which was favorable to improve the catalytic activities of MnO-CeO/ACFN. The experimental results show that the conversion of NO is nearly 100% in the range 100°C–150°C under the optimal preparation conditions of MnO-CeO/ACFN. In addition, the effects of a series of performance parameters, including initial NH concentration, NO concentration and O concentration, on the conversion of NO were studied.

关键词: preparation     conversion     favorable     selective catalytic     MnO-CeO/ACFN    

Enhanced performances in catalytic oxidation of

Nanli QIAO,Xin ZHANG,Chi HE,Yang LI,Zhongshen ZHANG,Jie CHENG,Zhengping HAO

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 458-466 doi: 10.1007/s11783-015-0802-1

摘要: A series of hierarchical macro-/mesoporous silica supports (MMSs) were successfully synthesized using dual-templating technique employing polystyrene (PS) spheres and the Pluronic P123 surfactant. Pd was next loaded on the hierarchical silica supports via colloids precipitation method. Physicochemical properties of the synthesized samples were characterized by various techniques and all catalysts were tested for the total oxidation of -xylene. Among them, the Pd/MMS-b catalyst with tetraethoxysilane/polystyrene weight ratio of 1.0 exhibited superior catalytic activity, and under a higher gas hourly space velocity (GHSV) of 70000 h , the 90% conversion of -xylene has been obtained at around 200°C. The BET and SEM results indicated that Pd/MMS-b catalyst possesses high surface area and large pore volume, and well-ordered, interconnected macropores and 2D hexagonally mesopores hybrid network. This novel ordered hierarchical porous structure was highly beneficial to the dispersion of active sites Pd nanoparticles with less aggregation, and facilitates diffusion of reactants and products. Furthermore, the Pd/MMS-b catalyst possessed good stability and durability.

关键词: hierarchical macro-/mesoporous     silica     palladium     VOCs catalytic oxidation    

Selective catalytic reduction of NO

Pavlo I. Kyriienko

《化学科学与工程前沿(英文)》 2020年 第14卷 第4期   页码 471-491 doi: 10.1007/s11705-019-1847-7

摘要: Research results regarding selective catalytic reduction (SCR) of NO with ethanol and other C oxygenates as reductants over silver-alumina catalysts are summarized. The aspects of the process mechanism, nature of active sites, role of alumina and silver (especially in the formation of bifunctional active sites), effects of reductants and reaction conditions are discussed. It has been determined that key stages of the process include formation of reactive enolic species, their interaction with NO and formation of nitroorganic compounds which transform to NCO species and further to N . The results obtained over various silver-alumina catalysts demonstrate the perspectives of their application for reducing the level of nitrogen oxides in engine emissions, including in the presence of water vapor and sulfur oxides. Ways to improve the catalysts for the SCR of NO with C oxygenates are outlined.

关键词: SCR     nitrogen oxides     silver-alumina catalyst     silver species     ethanol     oxygenates    

β-Cyclodextrin promoted oxidation of primary amines to nitriles in water

Dongpo SHI, Hongbing JI, Zhong LI

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 196-200 doi: 10.1007/s11705-009-0051-6

摘要: A facile, efficient and substrate-selective oxidation of the primary amines with NaClO as oxidant catalyzed by cyclodextrin ( CD) has been developed in water for the first time, and the behavior of cyclodextrin that catalyzed the primary amines to nitriles in water was investigated. It was found that the primary amines which could form host-guest complexes with cyclodextrin were oxidized to nitriles with excellent yields at ambient temperature. The results show that cyclodextrin worked not only as a solubilizing agent but also as a catalyst in these reactions.

关键词: substrate-selective     amines oxidation     β-cyclodextrin    

标题 作者 时间 类型 操作

Effect of Cu-ZSM-5 catalysts with different CuO particle size on selective catalytic oxidation of N,N-Dimethylformamide

期刊论文

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selectivecatalytic oxidation of cyclohexane

期刊论文

Multi-stage ammonia production for sorption selective catalytic reduction of NO

Chen ZHANG, Guoliang AN, Liwei WANG, Shaofei WU

期刊论文

Effects of support acidity on the reaction mechanisms of selective catalytic reduction of NO by CH

Shicheng XU, Junhua LI, Dong YANG, Jiming HAO

期刊论文

Transition metal-doped heteropoly catalysts for the selective oxidation of methacrolein to methacrylic

Yanxia Zheng,Heng Zhang,Lei Wang,Suojiang Zhang,Shaojun Wang

期刊论文

Effect of different acid anions on highly efficient Ce-based catalysts for selective catalytic reduction

期刊论文

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selectivecatalytic reduction of NO

期刊论文

Microwave-assisted catalytic oxidation of gaseous toluene with a Cu-Mn-Ce/cordierite honeycomb catalyst

Longli Bo, Shaoyuan Sun

期刊论文

Design and operational considerations for selective catalytic reduction technologies at coal-fired boilers

Jeremy J. SCHREIFELS, Shuxiao WANG, Jiming HAO

期刊论文

Catalytic oxidation of

Na Li, Xin Xing, Yonggang Sun, Jie Cheng, Gang Wang, Zhongshen Zhang, Zhengping Hao

期刊论文

Metal-organic framework loaded manganese oxides as efficient catalysts for low-temperature selectivecatalytic reduction of NO with NH

Minhua Zhang, Baojuan Huang, Haoxi Jiang, Yifei Chen

期刊论文

Low-temperature selective catalytic reduction of NO with NH based on MnO-CeO/ACFN

SHEN Boxiong, LIU Ting, SHI Zhanliang, SHI Jianwei, YANG Tingting, ZHAO Ning

期刊论文

Enhanced performances in catalytic oxidation of

Nanli QIAO,Xin ZHANG,Chi HE,Yang LI,Zhongshen ZHANG,Jie CHENG,Zhengping HAO

期刊论文

Selective catalytic reduction of NO

Pavlo I. Kyriienko

期刊论文

β-Cyclodextrin promoted oxidation of primary amines to nitriles in water

Dongpo SHI, Hongbing JI, Zhong LI

期刊论文