检索结果-南通市图书馆

catalytic urea hydrolysis by composite metal oxide catalyst towards efficient urea-based SCR process:performance evaluation and mechanism investigation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2023年第5期17卷 67-80页

作者： Yuchen Li Zhen Chen Xiangyu Zhang Kun Yang Lidong Wang Junhua Li MOE Key Laboratory of Resources and Environmental Systems Optimization Department of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Xi’an Thermal Power Research Institute Co. Xi’an 710032China

As a promising option to provide gaseous NH_(3) for SCR system,catalytic urea hydrolysis has aroused great attention,and improving surface area and activity of catalysis are the crucial issues to be solved for efficient urea hydrolysis.Therefore,a composite metal oxide(TiO_(2)@Al_(2)O_(3))catalyst was prepared by a simple hydrothermal method,with mesoporous alumina(γ-Al_(2)O_(3))as substrate.The results verify the mesoporous structure and submicron cluster of TiO_(2)@Al_(2)O_(3),with exposed crystal faces of(101)and(400)for TiO_(2)andγ-Al_(2)O_(3),respectively.The electronegativity difference of Ti4+and Al3+changes the charge distribution scheme around the interface,which provides abundant acid/base sites to boost the urea hydrolysis.Consequently,for an optimal proportioning with nano TiO_(2)content at 10 wt.%,the hydrolysis efficiency can reach up to 35.2%at 100℃ in 2 h,increasing by~7.1%than that of the blank experiment.^(13)C NMR spectrum measurements provide the impossible intermediate species during urea hydrolysis.Theoretical calculations are performed to clarify the efficient H_(2)O decomposition at the interface of TiO_(2)@Al_(2)O_(3).The result offers a favorable technology for energy-efficiency urea hydrolysis.

关键词： SCR Urea hydrolysis catalytic Water dissociation Electronegativity

catalytic recycling of polyesters via a binuclear catalyst

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第2期67卷 426-427页

作者： Bo Sun Ding Ma Beijing National Laboratory for Molecular Science New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

Plastics play a crucial role in modern society life. While the increasing use of plastics and rapid accumulation of plastic waste in nature environment have caused severe environmental crisis and the waste of carbon resources. catalytic upcycling is a promising approach to transform plastic waste into high value-added chemicals to achieve a sustainable circular economy.

关键词： catalytic polyester catalyst

catalytic bed slenderness ratio and ADN/methanol ratio for decomposition and combustion characteristics within ammonium dinitramide(ADN)-based green aerospace thruster

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第5期27卷 1159-1165页

作者： Jun Chen Guoxiu Li Tao Zhang Yinglong Liu Rui Yang Yang Chen School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Control Engineering Beijing 100190China Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology Beijing 100190China

The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and operation parameters (mass fraction ratio of ADN/CH3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure-mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed w让h a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance. These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.

关键词： ADN-based thruster catalytic bed structure Operation parameters Decomposition and combustion Thruster

catalytic Enantioselective Formal Synthesis of MDM2 Antagonist RG7388 and Its Analogues

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2020年第5期38卷 435-438页

作者： Xue-Jie Zou Wu-Lin Yang Jing-Yan Zhu Wei-Ping Deng Shanghai Key Laboratory of New Drug Design and School of Pharmacy East China University of Science and Technology130 Meilong RoadShanghai 200237China

The catalytic asymmetric 1,3-dipolar[3+2]cycloaddition of azomethine ylides with stilbenes has been established,affording structurally diverse pyrrolidines bearing four contiguous stereocenters with stereo-diversity in generally high yields and good to excellent stereoselectivities(up to 98%yield,99:1 dr,>99%ee).Meanwhile,this strategy allowed the formal synthesis of antitumor drug RG7388(PhaseⅢclinical study)and its analogues in high efficiency.

关键词： stereo catalytic allowed

catalytic effect of SrTiO_3 on the hydrogen storage behaviour of MgH_2

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2019年第1期28卷 46-53页

作者： M.S.Yahya M.Ismail School of Ocean Engineering University Malaysia Terengganu

The effects of Sr TiO_3 on the hydrogen storage properties of MgH_2 have been studied for the first time.The onset dehydrogenation temperature of the MgH_2-10 wt% SrTiO_3 is found to be 275 ℃, which is 55 ℃ lower as compared to the as-milled MgH_2. The composite is able to absorb 4.3 wt% of hydrogen in 60 min instead of 1.1 wt% for the as-milled Mg H_2. Meanwhile, the composite is able to release 5.3 wt% of hydrogen in 17 min compared to 1.9 wt% by the as-milled Mg H_2 at 320 ℃. The calculated Eaof the Mg H_2-10 wt% SrTiO_3 is 109 k J/mol, which is 26.3 kJ/mol lower than the calculated Eaof the as-milled MgH_2. The Sr TiO_3 is not decomposed during the ball milling and the re/dehydrogenation processes. The catalytic effect shown by the SrTiO_3 is owing to its ability to change the physical structure of the MgH_2 particles during the ball milling process.

关键词： Hydrogen storage Magnesium hydride catalytic effect Sorption properties

catalytic performance of Zr-doped CuO-CeO2 oxides for CO selective oxidation in H2-rich stream

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第7期37卷 720-725页

作者： Limin Shi Chuanlei Gao Fenghai Guo Yujing Wang Tiebang Zhang School of Materials and Chemical Engineering Xi’an Technological UniversityXi'an 710021China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

Zr-doped CuO-CeO2 catalysts for CO selective oxidation were designed and prepared by the hydrothermal method and coprecipitation. The experimental samples were characterized by means of N2 adsorption-desorption isotherms, powder X-ray diffraction, temperature-programmed reduction and Xray photoelectron spectroscopy. It is observed that the catalyst prepared by hydrothermal method exhibits larger specific surface area, smaller crystalline size and higher dispersion of active components compared with those of the catalyst obtained by coprecipitation. Meanwhile, redox properties of copper oxide are improved significantly and highly dispersed copper species providing CO oxidation sites are present on the surface. Furthermore, adsorptive centers of CO and active oxygen species increase on the copper-ceria interfaces. The Zr-doped CuO-CeO2 catalyst prepared by hydrothermal method possesses superior catalytic activity and selectivity for selective oxidation of CO at low temperature compared with those of the sample prepared by coprecipitation. The temperature corresponding to 50% CO conversion is only 73 ℃ and the temperature span of total CO conversion is expanded from 120 to 160 ℃.

关键词： catalytic performance CuO-CeO2 oxides Zr doping CO selective oxidation Hydrogen purification Rare earths

catalytic wet oxidation of N,N-dimethyl formamide over ruthenium supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2 catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第3期37卷 265-272页

作者： Jiawen Gong Dongzhi Li Li Wang Wangcheng Zhan Yanglong Guo Yunsong Wang Yun Guo Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis School of Chemistry & Molecular Engineering East China University of Science and Technology

A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.

关键词： catalytic wet oxidation N,N-dimethyl formamide Ru Degradation Catalyst deactivation and regeneration Rare earths

Ultra-small UiO-66-NH_(2)nanoparticles immobilized on g-C_(3)N_(4)nanosheets for enhanced catalytic activity

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2022年第3期7卷 512-518页

作者： Zhuizhui Su Bingxing Zhang Xiuyan Cheng Fanyu Zhang Qiang Wan Lifei Liu Xiuniang Tan Dongxing Tan Lirong Zheng Jianling Zhang Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Colloid and Interface and ThermodynamicsCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing100190China School of Chemical Sciences University of Chinese Academy of SciencesPhysical Science LaboratoryHuairou National ComprehensiveScience CenterBeijing100190China Beijing Synchrotron Radiation Facility(BSRF) Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China

UiO-66-NH_(2),an important metal-organic framework,is usually synthesized by solvothermal method and the particle size is generally larger than 200 nm,which limits its catalytic applications in chemical reactions.It is very meaningful to produce UiO-66-NH_(2) nanoparticles with ultrasmall size,but remains challenging.Herein,we synthesized UiO-66-NH_(2) nanoparticles in size of 8-15 nm that are immobilized on g-C_(3)N_(4)nanosheets.Compared with the UiO-66-NH_(2) synthesized by the traditional solvothermal method(>200 nm),the ultra-small UiO-66-NH_(2) nanoparticles immobilized on g-C_(3)N_(4)have more unsaturated coordination positions and increased Lewis acidity.Owing to these combined advantages,the ultra-small UiO-66-NH_(2)nanoparticles exhibit greatly improved catalytic activity for Meerwein-Ponndorf-Verley reaction than larger UiO-66-NH_(2)particles.

关键词： particles catalytic meaningful

Mechanistic study of vacuum UV catalytic oxidation for toluene degradation over CeO_(2) nanorods

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2022年第3期7卷 533-544页

作者： Muyan Wu Yingguang Zhang Haibao Huang Dennis Y.C.Leung Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong KongChina School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou510275China

The present study specifically investigates vacuum ultraviolet (VUV) catalytic oxidation for toluene degradation over CeO_(2) nanorods.Synergetic effects of ultraviolet photocatalytic oxidation (UV-PCO) and ozone catalytic oxidation (OZCO) were manifested in the results of toluene removal and COx generation,while the combination of UV-PCO andOZCO (UV-OZCO) did not lead to improvement of mineralization.All the processes contribute to ozone decomposition,but no obvious synergetic effects of the different processes can be observed.Intermediate analysis results indicated that more toluene was oxidized into by-products,such as benzyl alcohol and benzaldehyde,by UV-OZCO rather than forming COx.Both hydroxyl radical (·OH) and superoxide radical (·O_(2)^(-)) were found in all the processes of the VUV-PCO-OZCO system(combination of VUV photolysis,UV-PCO,OZCO and UV-OZCO processes).In the UV-OZCO process,the formation of hydroxyl radical was promoted,while that of superoxide radical was impeded,resulting in lower mineralization level of toluene.The mechanistic study of toluene degradation over CeO_(2) nanorods in the VUV-PCO-OZCO system revealed that with the formation of·O_(2)^(-)and·OH,toluene is first oxidized to intermediates,followed by further ring–opening reaction and,finally,degradation into CO_(2) and H_(2)O.CeO_(2) nanorods function as both ozonation catalyst and photocatalyst,and the redox pair of Ce^(3+)and Ce^(4+)are interconvertible and can keep a balance.

关键词： toluene catalytic vacuum