Uv-visible characterization of gold exchanged in beta zeolite

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Ni, Co and Ni-Co-Modified Tungsten Carbides Obtained by an Electric Arc Method as Dry Reforming Catalysts

075-15-2021-710. Research on the synthesis of tungsten carbide was supported by the RF Ministry of Education and Science project No FSWW-2022-0018Dry reforming of methane (DRM), to produce synthesis gas, is one of the most important chemical reactions used for the industrial production of hydrogen and leads to the synthesis of hydrocarbons (liquid fuels) and other valuable products. A cost-effective alternative to active and stable noble metal DRM catalysts, with comparable catalytic performance, can be composite materials based on nickel, cobalt and transition metal carbides. In this line, the present work proposes a non-standard way to obtain dry reforming catalysts of Ni, Co and Ni-Co-modified tungsten carbide (WC) produced by an electric arc method. Different amounts of nickel, cobalt and their mixtures were deposited on tungsten carbide by deposition-precipitation with NaOH (DP) and incipient wetness impregnation (IWI) methods. The resulting materials were characterized by N2 adsorption-desorption, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, and their performance was evaluated in DRM. The composition and preparation method of catalysts predetermined their structural, textural and electronic properties, playing a decisive role in their activity for DRM. DP-prepared 20%Ni/WC material remained resistant to oxidation, both that of the active metal (nickel) and of the tungsten carbide, as well as to coking during DRM. This sample proved to be the most active and stable among all studied materials. Possibly, the resistance to oxidation and coking was due to a more efficient implementation of the oxidation/(re)carbonization cycle on the surface of this catalyst.publishersversionpublishe

Kinetic regularities, catalyst deactivation and reactivation

Funding text 1 The research is funded from Ministry of Education and Science of the Russian Federation Program No. 075–03–2021–287/6 (Russia). Funding text 2 XPS measurements were carried out at the Central laboratories of Tomsk Polytechnic University (Analytical Center). HRTEM was carried out at the Innovation centre for Nanomaterials and Nanotechnologies of Tomsk Polytechnic University. The ICP-OES analysis was carried out using the core facilities of “Physics and Chemical methods of analysis” of Tomsk Polytechnic University. Fundação para a Ciência e a Tecnologia for Scientific Employment Stimulus Institutional Call (CEECINST/00102/2018), UIDB/50006/2020 and UIDP/50006/2020 (LAQV), UIDB/00100/2020 and UIDP/00100/2020 (Centro de Química Estrutural).Betulin, being a pentacyclic triterpene alcohol and an extractive from birch bark, along with its oxo-derivatives, has a broad range of physiological properties of interest for synthesis of pharmaceuticals. Instead of oxidizing betulin with strong and toxic oxidizing agents the present study shows a possibility of using liquid-phase oxidation of betulin with air over supported Ag NPs catalysts as an alternative method for synthesis of its oxo-derivatives. Based on catalytic studies, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy, the evolution of the surface of nanosilver catalysts during the catalysis was demonstrated, as well as under the impact of reactant gas composition. The kinetic regularities and causes of deactivation of supported Ag NPs catalysts were revealed. An approach to the regeneration of silver catalysts was proposed. Kinetic analysis with numerical data fitting was performed resulting in an adequate description of the concentration dependencies.publishersversionpublishe

Oxidation of 5-hydroxymethylfurfural on supported ag, au, pd and bimetallic pd-au catalysts: Effect of the support

Fundacao para a Ciencia e Tecnologia (FCT), Portugal, through project UIDB/00100/2020 of the Centro de Quimica Estrutural; Associate Laboratory for Green Chemistry-LAQV,financed by national funds from FCT/MCTES (UIDB/50006/2020); FCT Scientific Employment Stimulus-Institutional Call (CEECINST/00102/2018) and PTDC/QEQ-QIN/3967/2014; Tomsk Polytechnic University Competitiveness Enhancement Program project VIU-RSCBMT-197/2020; Russian Foundation of Basic Research, project 18-29-24037; Tomsk Polytechnic University State Task `Science' (project FSWW-2020-0011) andMICINN project CTQ2017-86170-R (Spain).Oxidation of 5-hydroxymethylfurfural (HMF), a major feedstock derived from waste/fresh biomass, into 2,5-furandicarboxylic acid (FDCA) is an important transformation for the production of biodegradable plastics. Herein, we investigated the effect of the support (unmodified and modified titania, commercial alumina, and untreated and treated Sibunit carbon) of mono-and bimetallic catalysts based on noble metals (Ag, Au, Pd) on selective HMF oxidation with molecular oxygen to FDCA under mild and basic reaction conditions. The higher selectivity to FDCA was obtained when metals were supported on Sibunit carbon (Cp). The order of noble metal in terms of catalyst selectivity was: Ag < Au < Pd < PdAu. Finally, FDCA production on the most efficient PdAu NPs catalysts supported on Sibunit depended on the treatment applied to this carbon support in the order: PdAu/Cp < PdAu/Cp-HNO3 < PdAu/Cp-NH4OH. These bimetallic catalysts were characterized by nitrogen adsorption-desorption, inductively coupled plasma atomic emission spectroscopy, high resolution transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Hammet indicator method and X-ray photoelectron spectroscopy. The functionalization of Sibunit surface by HNO3 and NH4OH led to a change in the contribution of the active states of Pd and Au due to promotion effect of N-doping and, as a consequence, to higher FDCA production. HMF oxidation catalyzed by bimetallic catalysts is a structure sensitive reaction.publishersversionpublishe

Supported silver nanoparticles as catalysts for liquid-phase betulin oxidation

The research is funded from the Russian Science Foundation project No. 18-73-00019, Tomsk Polytechnic University Competitiveness Enhancement Program, project VIU-ISHBMT-197/2020 and Tomsk Polytechnic University State Task "Science", project FSWW-2020-0011 (Russia). This work was partially supported by Fundacao para a Ciencia e a Tecnologia, Portugal, through project UIDB/00100/2020 of the Centro de Quimica Estrutural, by national funds though FCT, under the Scientific Employment Stimulus-Institutional Call (CEECINST/00102/2018) and the Associate Laboratory for Green Chemistry-LAQV financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020).Herein, it has been shown that betulin can be transformed into its biologically active oxo-derivatives (betulone, betulinic and betulonic aldehydes) by liquid-phase oxidation over supported silver catalysts under mild conditions. In order to identify the main factors determining the catalytic behavior of nanosilver catalysts in betulin oxidation, silver was deposited on various alumina supports (γ-alumina and boehmite) using deposition–precipitation with NaOH and incipient wetness impregnation methods, followed by treatment in H2 or O2. Silver catalysts and the corresponding supports were characterized by X-ray diffraction, nitrogen physisorption, inductively coupled plasma optical emission spectroscopy, photoelectron spectroscopy and transmission electron microscopy. It was found that the support nature, preparation and treatment methods predetermine not only the average Ag nanoparticles size and their distribution, but also the selectivity of betulin oxidation, and thereby, the catalytic behavior of Ag catalysts. In fact, the support nature had the most considerable effect. Betulin conversion, depending on the support, increased in the following order: Ag/boehmite < Ag/boehmite (calcined) < Ag/γ-alumina. However, in the same order, the share of side reactions catalyzed by strong Lewis acid centers of the support also increased. Poisoning of the latter by NaOH during catalysts preparation can reduce side reactions. Additionally, it was revealed that the betulin oxidation catalyzed by nanosilver catalysts is a structure-sensitive reaction.publishersversionpublishe

The Effect of Sibunit Carbon Surface Modification with Diazonium Tosylate Salts of Pd and Pd-Au Catalysts on Furfural Hydrogenation

Funding Information: The research is funded by the Ministry of Education and Science of the Russian Federation Program № 075-03-2021-287/6. Sevastopol State University Research grant 42-01-09/169/2021-4 (Russia). Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Herein, we investigated the effect of the support modification (Sibunit carbon) with diazonium salts of Pd and Pd-Au catalysts on furfural hydrogenation under 5 bars of H2 and 50 °C. To this end, the surface of Sibunit (Cp) was modified with butyl (Cp-Butyl), carboxyl (Cp-COOH) and amino groups (Cp-NH2) using corresponding diazonium salts. The catalysts were synthesized by the sol immobilization method. The catalysts as well as the corresponding supports were characterized by Fourier transform infrared spectroscopy, N2 adsorption-desorption, inductively coupled plasma atomic emission spectroscopy, high resolution transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Hammet indicator method and X-ray photoelectron spectroscopy. The analysis of the results allowed us to determine the crucial influence of surface chemistry on the catalytic behavior of the studied catalysts, especially regarding selectivity. At the same time, the structural, textural, electronic and acid–base properties of the catalysts were practically unaffected. Thus, it can be assumed that the modification of Sibunit with various functional groups leads to changes in the hydrophobic/hydrophilic and/or electrostatic properties of the surface, which influenced the selectivity of the process.publishersversionpublishe

Effect of the metal deposition order on structural, electronic and catalytic properties of tio2-supported bimetallic au-ag catalysts in 1-octanol selective oxidation

42-01-09/169/2021-4 CTQ2017-86170-RAu and Ag were deposited on TiO2 modified with Ce, La, Fe or Mg in order to obtain bimetallic catalysts to be used for liquid-phase oxidation of 1-octanol. The effects of the deposition order of gold and silver, and the nature of the support modifying additives and redox pretreatments on the catalytic properties of the bimetallic Au-Ag catalysts were studied. Catalysts were characterized by low-temperature nitrogen adsorption–desorption, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy. It was found that pretreatments with hydrogen and oxygen at 300◦C significantly decreased the activity of AuAg catalysts (silver was deposited first) and had little effect on the catalytic properties of AgAu samples (gold was deposited first). The density functional theory method demonstrated that the adsorption energy of 1-octanol increased for all positively charged AuxAgyq (x + y = 10, with a charge of q = 0 or +1) clusters compared with the neutral counterparts. Lanthanum oxide was a very effective promoter for both monometallic and bimetallic gold and silver catalysts in the studied process.publishersversionpublishe

Компетентностный подход и проблемы его реализации в высшей школе

Currently, the vocational education system is based on a competency-based approach, which considers the person»s ability to act productively in a professional situation rather than the amount of information learned as the result of education. The term «competency», as an indicator of the result of training, was introduced in the Russian Federation in 2009, with the introduction of the state educational standards for higher education of the first generation (Federal State Educational Standard), at the same time as the graduate students» competency model was introduced. Competence-based education implies competence-based orientation of both the content of the educational process and the methods of its implementation, as well as assessment procedures, means of assessing the quality of students» training, since the goals and the content of education, the organization of the educational process that are provided by educational standards, determine the results of education in the form of competencies. The implementation of the standards of competencies set in the Federal State Educational Standard of Higher Education in the actual learning process proved to be not so simple. Difficulties arise when relating the goals of education with the expected results, i.e., competencies. The difficulties are associated with the mismatch between the practical orientation of the competence-based approach and the existing subject-based orientation of the pedagogical practice. In the course of studying a specific discipline, the opportunity to fully form a speicfic competency, not a set of competencies specified by the Federal State Educational Standard, but also a specific competence, is small.However, the main difficulty is associated with the assessment of the level of competence formation. A competence-based approach requires measuring not only specific knowledge and skills of students, but an assessment of the qualities of the person him- or herself. However, the existing system for assessing the quality of education does not have the necessary assessment tools for this. This article discusses the issues of competence-based education in higher education, analyzes its features, and problems raleted to the assessment of the level of competence formation.В настоящее время система профессионального образования строится на компетентностном подходе, который в качестве результатов образования рассматривает не сумму усвоенной информации, а способность человека продуктивно действовать в профессиональной ситуации. Термин «компетенция», как показатель результата обучения, введен в РФ с 2009 г., с внедрением государственных образовательных стандартов высшего образования первого поколения (ФГОС), тогда же появляется компетентностная модель выпускника. Компетентностно-ориентированное образование подразумевает компетентностную ориентацию как содержания образовательного процесса и технологий его реализации, так и оценочных процедур, средств оценки качества подготовки обучающихся, поскольку цели и содержание образования, организация образовательного процесса, заданные образовательными стандартами, определяют результаты образования в форме компетенций. Переход от формулировок компетенций в ФГОС ВО к реальному процессу обучения оказался не таким простым. При соотнесении целей образования с предполагаемыми результатами - компетенциями возникают проблемы. Сложности связаны с несоответствием практической ориентированности компетентностного подхода и существующей предметной ориентацией педагогической практики. В ходе изучения конкретной дисциплины возможность сформировать в полной мере отдельную компетенцию не только набор компетенций, заданных ФГОС ВО, но и отдельную компетенцию - минимальна. Но основная сложность связана с диагностикой уровня сформированности компетенций. Компетентностный подход требует измерения не отдельных знаний, умений и навыков обучающихся, а оценки качеств самого человека. Однако существующая система оценки качества образования не имеет для этого необходимых оценочных средств. В представленной статье рассматриваются вопросы компетентностно-ориентированного образования в высшей школе, анализируются его особенности, проблемы диагностики уровня сформированности компетенций