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Effect of diluent and reaction parameter on selective oxidation of propane over MoVTeNb catalyst using nanoflow catalytic reactor

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Journal of Natural Gas Chemistry 2008年第2期17卷 130-134页

作者： Restu Kartiko Widi Sharifah Bee Abdul Hamid robert schlgl Department of Mathematic and Natural Science University of SurabayaTG 6th floor Raya Kalirungkut 60293SurabayaIndonesia Combinatorial Technology and Catalysis Research Centre University of Malaya50603Kuala LumpurMalaysia combinatorial Technology and Catalysis Research Centre University of Malaya50603Kuala LumpurMalaysia: Fritz-Haber-Institute der Max-Planck-Gesellschaft Faradayweg 4-614195 BerlinGermany

The selective oxidation of propane to acrylic acid over an MoVTeNb mixed oxide catalyst, dried and calcined before reaction has been studied using high-throughput instrumentation, which is called nanoflow catalytic reactor. The effects of catalyst dilution on the catalytic performance of the MoVTeNb mixed oxide catalyst in selective oxidation of propane to acrylic acid were also investigated. The effects of some reaction parameters, such as gas hourly space velocity （GHSV） and reaction temperature, for selective oxidation of propane to acrylic acid over diluted MoVTeNb catalyst have also been studied. The configuration of the nanoflow is shown to be suitable for screen catalytic performance, and its operating conditions were mimicked closely to conventional laboratory as well as to industrial conditions. The results obtained provided very good reproducibility and it showed that preparation methods as well as reaction parameters can play significant roles in catalytic performance of these catalysts.

关键词： selective oxidation propane acrylic acid MoVTeNb mixed oxide catalyst

ChemSuChem-a memorial to Dangsheng Su

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Journal of Energy Chemistry 2021年第10期30卷 250-252,I0008页

作者： robert schlögl Bingsen Zhang Qiang Zhang Xinhe Bao Department of Inorganic Chemistry Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4-614195 BerlinGermany Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory of Catalysis CAS Center for Excellence in NanoscienceDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Whoever met Dangsheng Su(D.S.)will remember this encounter with a personality that brought together the *** Chinese Austrian got to know and estimate the fine details of the small German-speaking culture within the We... 详细信息

关键词： remember details Eastern

Probing the intrinsic catalytic activity of carbon nanotubes for the metal-free oxidation of aromatic thiophene compounds in ionic liquids

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Journal of Energy Chemistry 2019年第5期28卷 131-137页

作者： Qingqing Gu Yuxiao Ding Zigeng Liu Yangming Lin robert schlogl Saskia Heumann Dangsheng Su Shenyang National Laboratory for Material Science Institute of Metal ResearchChinese Academy of SciencesWenhua Road 72Shenyang 110016LiaoningChina University of Chinese Academy of Sciences Beijing 100049China Max Planck Institute for Chemical Energy Conversion Stiftstrasse 34-3645470 Millheim a.d.RuhrGermany Fritz Haber Institute of the Max Planck Society Faradayweg 4-614195 BerlinGermany

A metal-free catalytic system combining oxidized carbon nanotubes (oCNTs) and ionic liquids (ILs) is presented for the oxidation of aromatic thiophene compounds with H2O2 as an oxidant. The oCNTs exhibit impressively high activity and stability in the system, which show an even better performance than those of some reported metal catalysts. The ILs are proved to have indispensable influence on the enhanced catalytic performance of the oCNTs. Detailed characterization by TG-MS and XPS demonstrates that the carbonyl groups are the active sites for the oxidation process, which is further supported by the deactivation and the model catalysts experiments. The quantitative analysis of different oxygen groups in oCNTs could be achieved by an isothermal temperature programmed TG-MS method. The concentration of carbonyl groups is 1.46 mmol per 1 g oCNTs and the tuiriover frequency of oCNTs could also be obtained (10.7 h^-1 in the presence of OmimPF6). H2O2 decomposition experiments combined with the EPR results reveal that the presence of OmimPF6 can avoid the intermediate HO· to form O2 and then improve the catalytic performance of oCNTs for the oxidation of dibenzothiophene.

关键词： Carbon nanotubes Metal-free catalysis Oxidative desulfurization Ionic liquids

Visualizing the importance of oxide-metal phase transitions in the production of synthesis gas over Ni catalysts

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Journal of Energy Chemistry 2020年第11期29卷 178-186页

作者： Luis Sandoval-Diaz Milivoj Plodinec Danail Ivanov Stephane Poitel Adnan Hammud Hannah C.Nerl robert schldgl Thomas Lunkenbein Department of Inorganic Chemistry Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4-614195 BerlinGermany Electron Spectrometry and Microscopy Laboratory School of Basic SciencesEcole Polytechnique Federale de Lausanne1015 LausanneSwitzerland Max Planck Institute for Chemical Energy Conversion StiftstraJSe 34-3645470 Miihlheim a.d.RuhrGermany

Synthesis gas, composed of H2 and CO, is an important fuel which serves as feedstock for industrially relevant processes, such as methanol or ammonia synthesis. The efficiency of these reactions depends on the H2: CO ratio, which can be controlled by a careful choice of reactants and catalyst surface ***, using a combination of environmental scanning electron microscopy(ESEM) and online mass spectrometry, direct visualization of the surface chemistry of a Ni catalyst during the production of synthesis gas was achieved for the first time. The insertion of a homebuilt quartz tube reactor in the modified ESEM chamber was key to success of the setup. The nature of chemical dynamics was revealed in the form of reversible oxide-metal phase transitions and surface transformations which occurred on the performing catalyst. The oxide-metal phase transitions were found to control the production of synthesis gas in the temperature regime between 700 and 900 ℃ in an atmosphere relevant for dry reforming of methane(DRM, CO2: CH4=0.75). This was confirmed using high resolution transmission electron microscopy imaging, electron energy loss spectroscopy, thermal analysis, and C18O2 labelled *** dedicated operando approach of simultaneously studying the surface processes of a catalyst and its activity allowed to uncover how phase transitions can steer catalytic reactions.

关键词： Dry reforming of methane Partial oxidation of methane Environmental scanning electron microscopy Synthesis gas Operando

Dynamic carbon surface chemistry: Revealing the role of carbon in electrolytic water oxidation

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Journal of Energy Chemistry 2020年第8期29卷 155-159,I0006页

作者： Yuxiao Ding Qingqing Gu Alexander Klyushin Xing Huang Sakeb H.Choudhury Ioannis Spanos Feihong Song Rik Mom Pascal Dungen Anna K.Mechler robert schlogl Saskia Heumann Max Planck Institute for Chemical Energy Conversion Stiftstrasse 34-36Mtilheim an der Ruhr 45470Germany Fritz-Haber-Institut der Max-Planck Gesellschaft Faradayweg 4-6Berlin 14195Germany Research Group Catalysis for Energy Helmholtz-Zentrum Berlin fur Materialien und Energie GmbHAlbert-Einstein-Strasse 1512489 BerlinGermany

Carbon materials have been widely used as electrodes, but the mechanistic roles are still not clear due to the complexity of the carbon surface chemistry. Herein we clarify that intrinsic material properties of carbon have to be activated by extrinsic factors. Pure carbon has no catalytic activity when used as electrode for electrocatalytic water oxidation. The evolution of oxygen functional groups on the carbon surface with increasing potential and the subsequent formation of real active sites with iron impurities from the electrolyte have been confirmed. These in-situ formed active sites protect the carbon from deep oxidation. This unprecedented finding not only provides insight into the dynamic evolution of carbon electrode surface chemistry and raises awareness of the need for detailed surface analysis under operando conditions, but also suggests a direction for the development of scalable and high-performance carbonbased electrode systems for various electrochemical applications.

关键词： Carbon chemistry Carbon catalysis Carbon electrode Water splitting Iron impurity

Predicting the coefficient of friction in a sliding contact by applying machine learning to acoustic emission data

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Friction 2024年第6期12卷 1299-1321页

作者： robert GUTIERREZ Tianshi FANG robert MAINWARING Tom REDDYHOFF Tribology Group Department of Mechanical EngineeringImperial College LondonExhibition RoadLondon SW72AZUK Shell global Solutions(US)Inc.Shell Technology Center Houston 3333 Highway 6 SouthHoustonTX 77082USA Shell International Petroleum Company Limited Shell CentreYork RoadLondon SE17NAUK

It is increasingly important to monitor sliding interfaces within machines,since this is where both energy is lost,and failures *** emission(AE)techniques offer a way to monitor contacts remotely without requiring transparent or electrically conductive ***,acoustic data from sliding contacts is notoriously complex and difficult to ***,we simultaneously measure coefficient of friction(with a conventional force transducer)and acoustic emission(with a piezoelectric sensor and high acquisition rate digitizer)produced by a steel‒steel rubbing *** data is then used to train machine learning(ML)algorithms(e.g.,Gaussian process regression(GPR)and support vector machine(SVM))to correlated acoustic emission with *** training requires the dense AE data to first be reduced in size and a range of processing techniques are assessed for this(e.g.,down-sampling,averaging,fast Fourier transforms(FFTs),histograms).Next,fresh,unseen AE data is given to the trained model and the resulting friction predictions are compared with the directly measured *** is excellent agreement between the measured and predicted friction when the GPR model is used on AE histogram data,with root mean square(RMS)errors as low as 0.03 and Pearson correlation coefficients reaching ***,predictions remain accurate despite changes in test conditions such as normal load,reciprocating frequency,and stroke *** paves the way for remote,acoustic measurements of friction in inaccessible locations within machinery to increase mechanical efficiency and avoid costly failure/needless maintenance.

关键词： acoustic emission condition monitoring friction machine learning Gaussian process regression support vector machine

A general mirror equivalence theorem for coset vertex operator algebras

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Science China Mathematics 2024年第10期67卷 2237-2282页

作者： robert McRae Yau Mathematical Sciences Center Tsinghua UniversityBeijing 100084China

We prove a general mirror duality theorem for a subalgebra U of a simple conformal vertex algebra A and its commutant V=ComA(U).Specifically,we assume that A≌■_(i∈I)U_(i)■V_(i) as a U■V-module,where the U-modules Uiare simple and distinct and are objects of a semisimple braided ribbon category of Umodules,and the V-modules Viare semisimple and contained in a(not necessarily rigid) braided tensor category of *** also assume U=ComA(V).Under these conditions,we construct a braid-reversed tensor equivalence τ:u_(A)→v_(A),where u_(A)is the semisimple category of U-modules with simple objects Ui,i∈I,and v_(A)is the category of V-modules whose objects are finite direct sums of *** particular,the V-modules Viare simple and distinct,and v_(A)is a rigid tensor *** an application,we find a rigid semisimple tensor subcategory of modules for the Virasoro algebra at central charge 13+6p+6p^(-1),p∈Z_(≥2), which is braided tensor equivalent to an abelian 3-cocycle twist of the category of finite-dimensional ***,the Virasoro vertex operator algebra at central charge 13+6p+6p^(-1)is the PSL_(2)(C)-fixed-point subalgebra of a simple conformal vertex algebra w(-p),analogous to the realization of the Virasoro vertex operator algebra at central charge 13-6p-6p^(-1)as the PSL_(2)(C)-fixed-point subalgebra of the triplet algebra W(p).

关键词： vertex operator algebras coset conformal eld theory braid-reversed tensor equivalence Virasoro algebra

Necrotic enteritis and antibiotic-free production of broiler chickens:Challenges in testing and using alternative products

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Animal Nutrition 2024年第1期16卷 288-298页

作者： robert J.Moore School of Science RMIT University

The global trend towards raising broiler chickens without the use of in-feed antibiotics(IFAs) means that there is an ongoing need to develop alternative treatments capable of delivering the benefits that IFAs previously provided. IFAs supported the productivity performance of chickens and played a key role in maintaining their health. Necrotic enteritis(NE) is an important disease of broilers that affects health,productivity, and welfare, and was previously well controlled by IFAs. However, with the reduction in IFA use, NE is resurgent in some countries. Vaccines and various feed additives, including pre-, pro-, and postbiotics, phytobiotics, fatty acids, and phage therapies have been introduced as alternative methods of NE control. While some of these feed additives have specific activity against the NE pathogen, Clostridium perfringens, most have the more general goal of reinforcing gut health. Extensive reviews of the effects of many of these feed additives on gut health have been published recently. Hence, rather than cover previously well reviewed areas of research this review focuses on the challenges and pitfalls in undertaking experimental assessment of alternative NE treatments and translating laboratory research to real world commercial production settings. The review is based on the author's particular experience,reading, thoughts, and analysis of the available information and inevitably presents a particular understanding that is likely to be at odds with others thinking on these issues. It is put forward to stimulate thinking and discussion on the issues covered.

关键词： Necrotic enteritis Clostridium perfringens Vaccines Feed additive Farm management

A detailed rock density model of the Hong Kong territories

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Geodesy and Geodynamics 2024年第1期15卷 75-81页

作者： Albertini Nsiah Ababio robert Tenzer Department of Land Surveying and Geo-Informatics Hong Kong Polytechnic UniversityHong KongChina

We used the geological map and published rock density measurements to compile the digital rock density model for the Hong Kong *** then estimated the average density for the whole *** to our result,the rock density values in Hong Kong vary from 2101 to 2681 kg·m^(-3).These density values are typically smaller than the average density of 2670 kg·m^(-3),often adopted to represent the average density of the upper continental crust in physical geodesy and gravimetric geophysics *** finding reflects that the geological configuration in Hong Kong is mainly formed by light volcanic formations and lava flows with overlying sedimentary deposits at many locations,while the percentage of heavier metamorphic rocks is very low(less than 1%).This product will improve the accuracy of a detailed geoid model and orthometric heights.

关键词： Density model Rock types Gravimetric modeling Hong Kong