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Characterization and catalytic activity of soft-templated NiO-CeO

Luciano Atzori, Maria Giorgia Cutrufello, Daniela Meloni, Barbara Onida, Delia Gazzoli, Andrea Ardu, Roberto Monaci, Maria Franca Sini, Elisabetta Rombi

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 251-268 doi: 10.1007/s11705-020-1951-8

摘要: Nanosized NiO, CeO and NiO-CeO mixed oxides with different Ni/Ce molar ratios were prepared by the soft template method. All the samples were characterized by different techniques as to their chemical composition, structure, morphology and texture. On the catalysts submitted to the same reduction pretreatment adopted for the activity tests the surface basic properties and specific metal surface area were also determined. NiO and CeO nanocrystals of about 4 nm in size were obtained, regardless of the Ni/Ce molar ratio. The Raman and X-ray photoelectron spectroscopy results proved the formation of defective sites at the NiO-CeO interface, where Ni species are in strong interaction with the support. The microcalorimetric and Fourier transform infrared analyses of the reduced samples highlighted that, unlike metallic nickel, CeO is able to effectively adsorb CO , forming carbonates and hydrogen carbonates. After reduction in H at 400 °C for 1 h, the catalytic performance was studied in the CO and CO co-methanation reaction. Catalytic tests were performed at atmospheric pressure and 300 °C, using CO/CO /H molar compositions of 1/1/7 or 1/1/5, and space velocities equal to 72000 or 450000 cm ∙h ∙g . Whereas CO was almost completely hydrogenated in any investigated experimental conditions, CO conversion was strongly affected by both the CO/CO /H ratio and the space velocity. The faster and definitely preferred CO hydrogenation was explained in the light of the different mechanisms of CO and CO methanation. On a selected sample, the influence of the reaction temperature and of a higher number of space velocity values, as well as the stability, were also studied. Provided that the Ni content is optimized, the NiCe system investigated was very promising, being highly active for the CO co-methanation reaction in a wide range of operating conditions and stable (up to 50 h) also when submitted to thermal stress.

关键词: soft template method     NiO-CeO2 catalysts     CO and CO2 co-methanation     synthetic natural gas production    

Catalytic combustion of methane over a highly active and stable NiO/CeO

Xiuhui Huang, Junfeng Li, Jun Wang, Zeqiu Li, Jiayin Xu

《化学科学与工程前沿(英文)》 2020年 第14卷 第4期   页码 534-545 doi: 10.1007/s11705-019-1821-4

摘要: In the last decades, many reports dealing with technology for the catalytic combustion of methane (CH ) have been published. Recently, attention has increasingly focused on the synthesis and catalytic activity of nickel oxides. In this paper, a NiO/CeO catalyst with high catalytic performance in methane combustion was synthesized via a facile impregnation method, and its catalytic activity, stability, and water-resistance during CH combustion were investigated. X-ray diffraction, low-temperature N adsorption, thermogravimetric analysis, Fourier transform infrared spectroscopy, hydrogen temperature programmed reduction, methane temperature programmed surface reaction, Raman spectroscopy, electron paramagnetic resonance, and transmission electron microscope characterization of the catalyst were conducted to determine the origin of its high catalytic activity and stability in detail. The incorporation of NiO was found to enhance the concentration of oxygen vacancies, as well as the activity and amount of surface oxygen. As a result, the mobility of bulk oxygen in CeO was increased. The presence of CeO prevented the aggregation of NiO, enhanced reduction by NiO, and provided more oxygen species for the combustion of CH . The results of a kinetics study indicated that the reaction order was about 1.07 for CH and about 0.10 for O over the NiO/CeO catalyst.

关键词: methane combustion     NiO/CeO2 catalyst     interaction     oxygen vacancy     kinetic study    

Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

《环境科学与工程前沿(英文)》 2012年 第6卷 第2期   页码 156-161 doi: 10.1007/s11783-010-0295-x

摘要: A series of CeO supported V O catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH ). The effects of O and SO on catalytic activity were also studied. The catalysts were characterized by specific surface areas (S ) and X–ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V O loading and calcination temperature. With the V O loading increasing from 0 to 10 wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400°C. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160°C–300°C. The formation of CeVO on the surface of catalysts caused the decrease of redox ability.

关键词: V2O5/CeO2 catalysts     NH3-SCR (selective catalytic reduction)     the incipient impregnation     low temperatures    

Al2O3 and CeO2-promoted MgO sorbents for CO2 capture at moderate

Huimei Yu, Xiaoxing Wang, Zhu Shu, Mamoru Fujii, Chunshan Song

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 83-93 doi: 10.1007/s11705-017-1691-6

摘要: A series of Al O and CeO modified MgO sorbents was prepared and studied for CO sorption at moderate temperatures. The CO sorption capacity of MgO was enhanced with the addition of either Al O or CeO . Over Al O -MgO sorbents, the best capacity of 24.6 mg-CO /g-sorbent was attained at 100 °C, which was 61% higher than that of MgO (15.3 mg-CO /g-sorbent). The highest capacity of 35.3 mg-CO /g-sorbent was obtained over the CeO -MgO sorbents at the optimal temperature of 200 °C. Combining with the characterization results, we conclude that the promotion effect on CO sorption with the addition of Al O and CeO can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO increased the basicity of MgO phase, resulting in more increase in the CO capacity than Al O promoter. Both the Al O -MgO and CeO -MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO sorption-desorption cycles. Compared to Al O , CeO is more effective for promoting the CO capacity of MgO. To enhance the CO capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area.

关键词: CO2 capture     MgO sorbents     Al2O3     CeO2     flue gas    

Interface engineering for enhancing electrocatalytic oxygen evolution reaction of CoS/CeO heterostructures

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 376-383 doi: 10.1007/s11705-021-2062-x

摘要: To realize renewable energy conversion, it is important to develop low-cost and high-efficiency electrocatalyst for oxygen evolution reaction. In this communication, a novel bijunction CoS/CeO2 electrocatalyst grown on carbon cloth is prepared by the interface engineering. The interface engineering of CoS and CeO2 facilitates a rapid charge transfer from CeO2 to CoS. Such an electrocatalyst exhibits outstanding electrocatalytic activity with a low overpotential of 311 mV at 10 mA∙cm−2 and low Tafel slope of 76.2 mV∙dec–1, and is superior to that of CoS (372 mV) and CeO2 (530 mV) counterparts. And it has long-term durability under alkaline media.

关键词: interface engineering     CoS/CeO2     electrodeposition     electrocatalyst     oxygen evolution reaction    

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective

《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    

CeO doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1539-2

摘要:

• CeO2 doping significantly improved low-temperature NH3-SCR activity on FeTiOx.

关键词: NH3-SCR     CeO2 doping     Low-temperature NOx removal     Improved redox property     In situ XAFS analysis    

Cu-doped Bi/Bi2WO6 catalysts for efficient N2 fixation by photocatalysis

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1412-1422 doi: 10.1007/s11705-023-2312-1

摘要: In this paper, Cu-doped Bi2WO6 was synthesized via a solvothermal method and applied it in photocatalytic N2 immobilization. Characterization results showed the presence of a small amount of metallic Bi in the photocatalyst, indicating that the synthesized photocatalyst is actually Bi/Cu-Bi2WO6 composite. The doped Cu had a valence state of +2 and most likely substituted the position of Bi3+. The introduced Cu did not affect the metallic Bi content, but mainly influenced the energy band structure of Bi2WO6. The band gap was slightly narrowed, the conduction band was elevated, and the work function was reduced. The reduced work function improved the transfer and separation of charge carriers, which mainly caused the increased photoactivity. The optimized NH3 generation rates of Bi/Cu-Bi2WO6 reached 624 and 243 μmol·L–1·g–1·h–1 under simulated solar and visible light, and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi2WO6, respectively. This research provides a method for improving the photocatalytic N2 fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N2-to-NH3 conversion.

关键词: Bi2WO6     Cu doping     work function     photocatalytic N2 fixation     charge separation    

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 289-296 doi: 10.1007/s11705-013-1345-2

摘要: Methane partial oxidation (MPO) is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H /CO ratio of 2. However, carbon deposition on a catalyst is observed as a major cause of catalyst deactivation in MPO. In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce Zr O (CZO) supported catalysts were prepared via the co-impregnation (C) and sequential incipient wetness impregnation (S) methods. The amount of Ni loading was fixed at 15 wt-% whereas the amount of MgO loading was varied from 5 to 15 wt-%. The results revealed that the addition of MgO shifted the light-off temperatures to higher temperatures. This is because the Ni surface was partially covered with MgO, and the strong interaction between NiO and NiMgO over CZO support led to the difficulty in reducing NiO to active Ni and thus less catalytic activity. However, among the catalysts tested, the 15Ni5Mg/CZO (S) catalyst exhibited the best catalytic stability for MPO after 18 h on stream at 750°C. Moreover, this catalyst had a better resistance to carbon deposition due to its high metallic Ni dispersion at high temperature.

关键词: methane partial oxidation     NiO     ceria-zirconia     MgO     mixed oxide solid solution    

用于CO甲烷化的Ni/CeO2催化剂还原过程重构行为调控研究 Article

曹昕宇, 浦天成, Bar Mosevitzky Lis, Israel E. Wachs, 彭冲, 朱明辉, 胡永康

《工程(英文)》 2022年 第14卷 第7期   页码 94-99 doi: 10.1016/j.eng.2021.08.023

摘要:

还原预处理是活化负载型金属催化剂的重要步骤,但很少受到关注。本研究发现负载型镍催化剂的重构过程对预处理条件非常敏感。与使用氢气的传统活化方式相比,用合成气活化催化剂可以产生具有多晶结构的负载型镍纳米颗粒,其中包含丰富的晶界。独特的活化方式使得催化剂上CO吸附得到增强,提高了CO甲烷化率。通过操纵活化条件来调整催化剂结构的策略也可以被用于指导其他负载型金属催化剂的理性设计。

关键词: 镍-氧化铈催化剂     催化剂活化     结晶性     甲烷化     原位谱学    

Effects of MgO promoter on properties of Ni/Al2O3 catalysts for partial oxidation of methane to syngas

QIU Yejun, CHEN Jixiang, ZHANG Jiyan

《化学科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 167-171 doi: 10.1007/s11705-007-0031-7

摘要: The effects of MgO promoter on the physico-chemical properties and catalytic performance of Ni/AlO catalysts for the partial oxidation of methane to syngas were studied by means of BET, XRD, H-TPR, TEM and performance evaluation. It was found that the MgO promoter benefited from the uniformity of nickel species in the catalysts, inhibited the formation of NiAlO spinel and improved the interaction between nickel species and support. These results were related to the formation of NiO MgO solid solution and MgAlO spinel. Moreover, for the catalysts with a proper amount of MgO promoter, the nickel dispersiveness was enhanced, therefore making their catalytic performance in methane partial oxidation improved. However, the excessive MgO promoter exerted a negative effect on the catalytic performance. Meanwhile, the basicity of MgO promoted the reversed water gas shift reaction, which led to an increase in CO selectivity and a decrease in H2 selectivity. The suitable content of MgO promoter in Ni/AlO catalyst was ?7 wt-%.

关键词: excessive     selectivity     decrease     dispersiveness     physico-chemical    

Electro-catalytic activity of CeO modified graphite felt for carbamazepine degradation via E-peroxone

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1410-x

摘要:

•CeOx/GF-EP process had the better degradation efficiency than GF-EP process.

关键词: E-peroxone     CeOx     Graphite felt     Carbamazepine     Mineralization    

Effects of preparation methods on the activity of CuO/CeO

Huanhuan Shang, Xiaoman Zhang, Jing Xu, Yifan Han

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 603-612 doi: 10.1007/s11705-017-1661-z

摘要: CO oxidation has been investigated on three CuO/CeO catalysts prepared by impregnation, co-precipitation and mechanical mixing. The origin of active sites was explored by the multiple techniques. The catalyst prepared by impregnation has more highly dispersed CuO and stronger interactions between CuO and CeO to promote the reduction of CuO to Cu species at the Cu-Ce interface, leading to its highest catalytic activity. For the catalyst prepared by co-precipitation, solid solution structures observed in Raman spectra suppress the formation of the Cu-Ce interface, where the adsorbed CO will react with active lattice oxygen to form CO , and thus it displays a lower catalytic performance. No Cu-Ce interface exists in the catalyst prepared by the mechanical mixing method due to the separate phases of CuO and CeO , resulting in its lowest activity among the three catalysts.

关键词: CuO/CeO2     CO oxidation     interfaces     structure-performance relationship     active sites    

Size and shape effects of MnFeO nanoparticles as catalysts for reductive degradation of dye pollutants

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 108-171 doi: 10.1007/s11783-021-1396-4

摘要: The magnetic nanoparticles that are easy to recycle have tremendous potential as a suitable catalyst for environmental toxic dye pollutant degradation. Rationally engineering shapes and tailoring the size of nanocatalysts are regarded as an effective manner for enhancing performances. Herein, we successfully synthesized three kinds of MnFe2O4 NPs with distinctive sizes and shapes as catalysts for reductive degradation of methylene blue, rhodamine 6G, rhodamine B, and methylene orange. It was found that the catalytic activities were dependent on the size and shape of the MnFe2O4 NPs and highly related to the surface-to-volume ratio and atom arrangements. Besides, all these nanocatalysts exhibit selectivity to different organic dyes, which is beneficial for their practical application in dye pollutant treatment. Furthermore, the MnFe2O4 NPs could be readily recovered by a magnet and reused more than ten times without appreciable loss of activity. The size and shape effects of MnFe2O4 nanoparticles demonstrated in this work not only accelerate further understanding the nature of nanocatalysts but also contribute to the precise design of nanoparticles catalyst for pollutant degradation.

关键词: Dye degradation     MnFe2O4 nanoparticles     Size and shape-control    

Mechanical properties characterization of different types of masonry infill walls

André FURTADO, Hugo RODRIGUES, António ARÊDE, Humberto VARUM

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 411-434 doi: 10.1007/s11709-019-0602-y

摘要: It is remarkable, the recent advances concerning the development of numerical modeling frameworks to simulate the infill panels’ seismic behavior. However, there is a lack of experimental data of their mechanical properties, which are of full importance to calibrate the numerical models. The primary objective of this paper is to present an extensive experimental campaign of mechanical characterization tests of infill masonry walls made with three different types of masonry units: lightweight vertical hollow concrete blocks and hollow clay bricks. Four different types of experimental tests were carried out, namely: compression strength tests, diagonal tensile strength tests, and flexural strength tests parallel and perpendicular to the horizontal bed joints. A total amount of 80 tests were carried out and are reported in the present paper. The second objective of this study was to compare the mechanical properties of as-built and existing infill walls. The results presented and discussed herein, will be in terms of strain-stress curves and damages observed within the tests. It was observed a fragile behavior in the panels made with hollow clay horizontal bricks, without propagation of cracks. The plaster increased the flexural strength by 57%.

关键词: masonry infill walls     experimental characterization     compression strength     shear diagonal strength     flexural strength    

标题 作者 时间 类型 操作

Characterization and catalytic activity of soft-templated NiO-CeO

Luciano Atzori, Maria Giorgia Cutrufello, Daniela Meloni, Barbara Onida, Delia Gazzoli, Andrea Ardu, Roberto Monaci, Maria Franca Sini, Elisabetta Rombi

期刊论文

Catalytic combustion of methane over a highly active and stable NiO/CeO

Xiuhui Huang, Junfeng Li, Jun Wang, Zeqiu Li, Jiayin Xu

期刊论文

Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

期刊论文

Al2O3 and CeO2-promoted MgO sorbents for CO2 capture at moderate

Huimei Yu, Xiaoxing Wang, Zhu Shu, Mamoru Fujii, Chunshan Song

期刊论文

Interface engineering for enhancing electrocatalytic oxygen evolution reaction of CoS/CeO heterostructures

期刊论文

Ultrasound-assisted co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective

期刊论文

CeO doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction

期刊论文

Cu-doped Bi/Bi2WO6 catalysts for efficient N2 fixation by photocatalysis

期刊论文

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

期刊论文

用于CO甲烷化的Ni/CeO2催化剂还原过程重构行为调控研究

曹昕宇, 浦天成, Bar Mosevitzky Lis, Israel E. Wachs, 彭冲, 朱明辉, 胡永康

期刊论文

Effects of MgO promoter on properties of Ni/Al2O3 catalysts for partial oxidation of methane to syngas

QIU Yejun, CHEN Jixiang, ZHANG Jiyan

期刊论文

Electro-catalytic activity of CeO modified graphite felt for carbamazepine degradation via E-peroxone

期刊论文

Effects of preparation methods on the activity of CuO/CeO

Huanhuan Shang, Xiaoman Zhang, Jing Xu, Yifan Han

期刊论文

Size and shape effects of MnFeO nanoparticles as catalysts for reductive degradation of dye pollutants

期刊论文

Mechanical properties characterization of different types of masonry infill walls

André FURTADO, Hugo RODRIGUES, António ARÊDE, Humberto VARUM

期刊论文