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Morphology effects in MnCeO_(x)solid solution-catalyzed NO reduction with CO:Active sites,water tolerance,reaction pathway

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Nano Research 2023年第5期16卷 6951-6959页

作者： Quanquan Shi Yifei Zhang Zhiwen Li Zhongkang Han Liangliang Xu alfons baiker Gao Li College of Science&College of Material Science and Art Design Inner Mongolia Agricultural UniversityHohhot 010018China College of Chemistry and Chemical Engineering Shenyang Normal UniversityShenyang 110034China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Department of Chemistry and Applied Biosciences Institute for Chemical and BioengineeringETH ZurichHönggerbergHClCH-8093 ZurichSwitzerland

Morphological effects of nanoparticles are crucial in many solid-catalyzed chemical *** herein prepared two manganese-ceria solid solutions,well-defined MnCeO_(x)nanorods and MnCeO_(x)-nanocubes,exposing preferentially(111)and(100)facets of ceria,*** incorporation of Mn dopant into ceria lattice strongly enhanced the catalytic performance in the NO reduction with ***_(x)(111)catalyst outperformed MnCeO_(x)(100)counterpart due to its higher population density of oxygen vacancy ***-situ infrared spectroscopy investigations indicated that the reaction pathway over MnCeO_(x)and pristine CeO_(2)is similar and that besides the direct pathway,an indirect pathway via adsorbed hyponitrite as an intermediate cannot be ruled out.X-ray photoelectron and Raman spectroscopies as well as first-principles density functional theory(DFT)calculations indicate that the enhanced catalytic performance of MnCeO_(x)can be traced back to its“Mn–OL(VÖ)–Mn–OL(VÖ)–Ce”*** Mn dopant strongly facilitates the formation of surface oxygen vacancies(VÖ)by liberating surface lattice oxygen(OL)via CO*+OL→CO_(2)*+VÖand promotes the reduction of NO,according to NO*+VÖ→N*+OL and 2N*→N_(2).The Mn dopant impact on both the adsorption of CO and activation of OL reveals that a balance between these two effects is critical for facilitating all reaction steps.

关键词： NO reduction with CO manganese-ceria solid solution morphology effects reaction mechanism active sites

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Nanostructured Ni-MoCx:An efficient non-noble metal catalyst for the chemoselective hydrogenation of nitroaromatics

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Nano Research 2023年第7期16卷 8919-8928页

作者： Yifei Zhang Zhiwen Li Jingjing Zhang Liangliang Xu Zhong-Kang Han alfons baiker Gao Li Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Department of Chemistry and Applied Biosciences Institute for Chemical and BioengineeringETH ZurichHönggerbergHClZurich CH-8093Switzerland University of Chinese Academy of Sciences Beijing 100049China

Catalysts for chemoselective hydrogenation are of vital importance for the synthesis of various important chemicals and *** we developed a simple method for preparing a highly efficient Ni-MoC_(x)nanocomposite catalyst via temperature-programmed carburization of a polyoxometalate precursor.X-ray diffraction(XRD),scanning transmission electron microscopy(STEM),X-ray photoelectron spectroscopy(XPS),and X-ray absorption spectroscopy(XAS)analyses indicate that the resulting mesoporous nanocomposite catalyst is made up of well-dispersed metallic nickel particles embedded in a MoC_(x)*** catalyst exhibits high activity and selectivity(>99%)in the hydrogenation of various substituted nitroaromatics to corresponding *** high efficiency is attributed to the intimate contact of the constituents favoring electron transfer and hydrogen *** is physisorbed on the carbide support and dissociates on the nickel particles,as evidenced by Mo K-edge X-ray absorption near-edge structure(XANES)spectra,density functional theory(DFT),and hydrogen-deuterium *** remarkable catalytic performance of the catalyst could be traced back to the synergistic interaction between the Ni particles and the carbide ***-situ infrared spectroscopy and DFT simulations indicated that the adsorption/activation of the nitro group is favored compared to that of other substituents at the aromatic *** recyclability tests,the Ni-MoC_(x)nanocomposite showed no significant loss of catalytic performance in seven consecutive runs,indicating its robust nature.

关键词： Ni-MoC_(x)nanocomposite carburization of polyoxometalate hydrogenation nitroaromatics synergistic effect

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Size hierarchy of gold clusters in nanogold-catalyzed acetylene hydrochlorination

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Nano Research 2024年第11期17卷 9594-9600页

作者： Yifei Zhang Xinrui Gu Fatimah Kehinde Busari Sami Barkaoui Zhong-Kang Han alfons baiker Zhen Zhao Gao Li Institute of Catalysis for Energy and Environment College of Chemistry and Chemical Engineering Shenyang Normal University Shenyang 110034 China State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China School of Materials Science and Engineering Zhejiang University Hangzhou 310000 China Department of Chemistry and Applied Biosciences ETH Hönggerberg HCI CH-8093 Zurich Switzerland University of Chinese Academy of Sciences Beijing 100049 China

Size hierarchy is a distinct feature of nanogold-catalysts as it can strongly affect their performance in various reactions. We developed a simple method to generate Au n S m nanoclusters of different sizes by thermal treatment of an Au144(PET)60 (PET: phenylethanethiol) parent cluster. These clusters, deposited on activated carbon, exhibit excellent catalytic performance in the hydrochlorination of acetylene. In-situ ultraviolet laser dissociation high-resolution mass spectrometry of the parent cluster in the presence of acetylene revealed a remarkable cluster size-dependence of acetylene adsorption, which is a crucial step in the hydrochlorination. Systematic density functional theory calculations of the reaction pathways on the differently-sized clusters provide deeper insight into the cluster size dependence of the adsorption energies of the reactants and afforded a scaling relationship between the adsorption energy of acetylene and the co-adsorption energies of the reactants (C_(2)H_(2) and HCl), which could enable a qualitative prediction of the optimal Au n S m cluster for the hydrochlorination of acetylene.

关键词： gold clusters size hierarchy AunSm acetylene hydrochlorination scaling relationship

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Continuous dimethyl carbonate synthesis from CO_(2) and methanol over Bi_(x)Ce_(1-x)O_(δ) monoliths:Effect of bismuth doping on population of oxygen vacancies,activity,and reaction pathway

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Nano Research 2022年第2期15卷 1366-1374页

作者： Yongdong Chen Yue Li Wei Chen Wen Wu Xu Zhong-kang Han Ammara Waheed Zhongbin Ye Gao Li alfons baiker College of Chemistry and Chemical Engineering Southwest Petroleum UniversityChengdu 610500China School of Physical Science and Technology Ningbo UniversityNingbo 315211China Center for Energy Science and Technology Skolkovo Institute of Science and TechnologySkolkovo Innovation CenterMoscow 143026Russia State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China ETH Zurich Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringHonggerbergHClCH-8093 ZurichSwitzerland

We evaluated bismuth doped cerium oxide catalysts for the continuous synthesis of dimethyl carbonate(DMC)from methanol and carbon dioxide in the absence of a dehydrating ***_(x)Ce_(1-x)O_(δ)nanocomposites of various compositions(x=0.06-0.24)were coated on a ceramic honeycomb and their structural and catalytic properties were *** incorporation of Bi species into the CeO_(2) lattice facilitated controlling of the surface population of oxygen vacancies,which is shown to play a crucial role in the mechanism of this reaction and is an important parameter for the design of ceria-based *** DMC production rate of the Bi_(x)Ce_(1-x)O_(δ) catalysts was found to be strongly enhanced with increasing Ov *** concentration of oxygen vacancies exhibited a maximum for Bi_(0.12)Ce_(0.88)O_(δ),which afforded the highest DMC production ***-term tests showed stable activity and selectivity of this catalyst over 45 h on-stream at 140°C and a gas-hourly space velocity of 2,880 mL·g_(cat)^(-1)·h^(-1).In-situ modulation excitation diffuse reflection Fourier transform infrared spectroscopy and first-principle calculations indicate that the DMC synthesis occurs through reaction of a bidentate carbonate intermediate with the activated methoxy(-OCH_(3))*** activation of C0_(2) to form the bidentate carbonate intermediate on the oxygen vacancy sites is identified as highest energy barrier in the reaction pathway and thus is likely the rate-determining step.

关键词： dimethyl carbonate synthesis bismuth-cerium oxides monolithic catalyst oxygen vacancies reaction mechanism

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High population and dispersion of pentacoordinated Al~Ⅴ species on the surface of ?ame-made amorphous silica-alumina

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Science Bulletin 2019年第8期64卷 516-523页

作者： Zichun Wang Yijiao Jiang Xianfeng Yi Cuifeng Zhou Aditya Rawal James Hook Zongwen Liu Feng Deng Anmin Zheng Michael Hunger alfons baiker Jun Huang School of Chemical and Biomolecular Engineering & Sydney Nano Institute The University of Sydney Department of Engineering Macquarie University State Key Laboratory Magnetic Resonance & Atomic Molecular Physics Wuhan Institute of Physics & Mathematics Chinese Academy of Sciences Mark Wainwright Analytical Centre University of New South Wales Institute of Chemical Technology University of Stuttgart Department of Chemistry and Applied Bioscience ETH Zürich

Pentacoordinated Al(Al~Ⅴ)species in silica-alumina are promising to promote the formation of acid sites or act as surface defects for tailoring single-atom ***,pentahedral coordination(Al~Ⅴ)is rarely observed in conventionally prepared ***,we show that high population and dispersion of Al~Ⅴ species on the surface of amorphous silica-alumina(ASA)can be achieved by means of flame spray *** resolution TEM/EDX,high magnetic-field NMR and DFT calculations are employed to characterize the structure of as-prepared ***-state ^(27)Al multi-quantum MAS NMR experiments show that most of the Al~Ⅴspecies are formed independently from the alumina phase and are accessible for guest molecules on the *** water adsorption,these Al~Ⅴ species are transformed to Al~Ⅵ species,structurally similar to surface Al~Ⅳ species,as confirmed by DFT *** outstanding catalytic activity of as-synthesized ASA is demonstrated using the in situ H/D exchange reaction with deuterated benzene as an *** Al~Ⅴ-rich ASA provides a much lower activation energy(～30 kJ/mol)than that reported for zeolite H-ZSM-5(～60 kJ/mol).The superior catalytic performance is attributed to the high Al~Ⅴcontent promoting the surface active sites in *** knowledge gained on the synthesis of Al~Ⅴ-rich ASAs and the nature of aluminum coordination in these materials could pave the way to more efficient silica-alumina based catalysts.

关键词： Amorphous silica-alumina Pentacoordinated Al~Ⅴ species 27Al multiple quantum magic-angle-spinning NMR H/D exchange

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Effect of welding parameters on the heat-affected zone of AISI409 ferritic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2012年第10期19卷 923-929页

作者： Eslam Ranjbarnodeh Stefanie Hanke Sabine Weiss alfons Fischer Young Researchers Club(East Tehran Branch) Islamic Azad UniversityTehran 33955-163Iran Materials Science and Engineering University of Duisburg-EssenDuisburg 47057Germany

One of the main problems during the welding of ferritic stainless steels is severe grain growth within the heat-affected zone （HAZ） In the present study, the microstmctural characteristics of tungsten inert gas （TIG） welded AISI409 ferritic stainless steel were investigated by electron backscattered diffraction （EBSD）, and the effects of welding parameters on the grain size, local misorientation, and low-angle grain boundaries were studied. A 3-D finite element model （FEM） was developed to predict the effects of welding parameters on the holding time of the HAZ above the critical temperature of grain growth. It is found that the base metal is not fully recrystallized. During the welding, complete recrystallization is followed by severe grain growth. A decrease in the number of low-angle grain boundaries is observed within the HAZ. FEM results show that the final state of residual sWains is caused by competition between welding plastic strains and their release by recrystallization. Still, the decisive factor for grain growth is heat input.

关键词： ferritic stainless steel welding heat affected zone recrystallization grain growth finite element method

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Deciphering fluid inclusions in high-grade rocks

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Geoscience Frontiers 2014年第5期5卷 683-695页

作者： alfons van den Kerkhof Andreas Kronz Klaus Simon Geowissenschaftliches Zentrum der Universitat Gottingen Goldschmidtstr.1-3 D 37073 GottingenGermany

The study of fluid inclusions in high-grade rocks is especially challenging as the host minerals have been normally subjected to deformation, recrystallization and fluid-rock interaction so that primary in- clusions, formed at the peak of metamorphism are rare. The larger part of the fluid inclusions found in metamorphic minerals is typically modified during uplift. These late processes may strongly disguise the characteristics of the ＂original＂ peak metamorphic fluid. A detailed microstructural analysis of the host minerals, notably quartz, is therefore indispensable for a proper interpretation of fluid inclusions. Cathodoluminescence （CL） techniques combined with trace element analysis of quartz （EPMA, LA- [CPMS） have shown to be very helpful in deciphering the rock-fluid evolution. Whereas high-grade metamorphic quartz may have relatively high contents of trace elements like Ti and A1, low- temperature re-equilibrated quartz typically shows reduced trace element concentrations. The result- ing microstructures in CL can be basically distinguished in diffusion patterns （along microfractures and grain boundaries）, and secondary quartz formed by dissolution-reprecipitation. Most of these textures are formed during retrograde fluid-controlled processes between ca. 220 and 500 ℃, i.e. the range of semi-brittle deformation （greenschist-facies） and can be correlated with the fluid inclusions. In this way modified and re-trapped fluids can be identified, even when there are no optical features observed under the microscope.

关键词： Fluid inclusionsGranuliteCharnockiteCathodoluminescenceLA-ICPMSQuartz

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Unusual presentation of localized gingival enlargement associated with a slow-growing odontogenic myxoma

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International Journal of Oral Science 2013年第3期5卷 172-175页

作者： Jaume Miranda Rius alfons Nadal Eduard Lahor Beatus Mtui Llu 's Brunet Departament d’Odontostomatologia Facultat d’Odontologia Universitat de Barcelona Servei d’Anatomia Patològica Hospital Clinic Facultat de Medicina Universitat de Barcelona Dental & Oral Department Soweto General Hospital Arusha Servei d’Odontologia Hospital Universitari Sant Joan de Déu Universitat de Barcelona

Unusual presentation of localized gingival enlargement associated with a subjacent tumoural pathology is *** patient was a55-year-old black male,whose chief complaint was a progressive gingival overgrowth for more than ten years,in the buccal area of the anterior left *** to the clinical features and the radiological diagnosis of odontogenic keratocyst,a conservative surgery with enucleation and curettage was *** submitted for histopathological analysis rendered the diagnosis of odontogenic *** 12-month of follow-up,no evidence of recurrence was *** should be cautious when facing any gingival enlargement to avoid diagnostic pitfalls and to indicate the appropriate treatment.

关键词： gingival enlargement jaw neoplasm odontogenic tumour myxoma myxofibroma

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Jacques Touret(1936-2024)

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Geoscience Frontiers 2024年第4期15卷 518-520页

作者： Maria Luce Frezzotti Daniel Harlov Jan Marten Huizenga alfons van den Kerkhof Universitàdegli Studi di Milano-Bicocca MilanoItaly Geo Forschungs Zentrum Potsdam TelegrafenbergPotsdamGermany Norwegian University of Life Sciences ÅsNorway Georg-August Universität Göttingen GöttingenGermany

Jacques Touret(Fig.1)passed away on 11 March 2024 in Paris at the age of 88 after a long *** is survived by his wife Lydie Touret,four children,and 14 *** was a pioneer in the field of fluid inclusions and its applications in high-grade metamorphic *** his retrospective paper in Geoscience Frontiers(Touret,2014),Jacques described himself as someone who dedicated"...a great part of my scientifiic life to the study of minute bubbles in rocks issued from the most extreme depths of our mother Earth".He will be remembered as a very amiable person and his infectious enthusiasm for fluid inclusions.

关键词： someone remember mother

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Optical Rotatory Dispersion Measurement of D-Glucose with Fixed Polarizer Analyzer Accessory in Conventional Spectrophotometer

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Journal of Analytical Sciences, Methods and Instrumentation 2013年第4期3卷 234-239页

作者： alfons Penzkofer Faculty of Physics University of Regensburg Regensburg Germany.

In the sample compartment of a conventional spectrophotometer, mounting of a polarizer before sample and an analyzer behind sample allows the determination of the optical rotatory dispersion of optical active media by measurement of the transmission ratio of crossed and parallel arranged polarizer and analyzer. A formula for the determination of the angle of rotation is derived from the transmission ratio. The arrangement is applied to determine the molar optical rotation of D-glucose in water in the wavelength range from 220 nm to 820 nm.

关键词： Optical Activity Optical Rotatory Dispersion Specific Optical Rotation Molar Optical Rotation Polarimeter Spectropolarimeter Grape Sugar D-Glucose

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