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The catalytic activity of nanostructured low percent (1%) Co-Ni catalysts on the basis of glass fiber (GF) prepared by a “solution combustion” (SC) method was studied. The catalytic activity of the prepared samples was studied in the reaction of dry reforming of methane (DRM) with CO2. The obtained samples were characterized by a number of physico-...
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... percentage (no more than 1%) species were synthe- sized by the SC method (Table 1, IK1-IK6). Glass fibers of a definite size were impregnated with a solution of cobalt and nickel nitrates, then dried for 30 min in air at 100 • C and then calcined in an air atmosphere at 400 • C. At this temperature the self propagating high temperature synthesis took place, re- sulting in the formation of nanoparticles with the size ranging from 30 to 100 nm [36−38]. ...
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... catalytic activity in the reaction of DRM was deter- mined for samples of catalysts presented in Table 1. Figures 8 and 9 present the results of the study of the dependence of the conversion of initial substrates, methane and carbon dioxide, as well as values of yields of target reaction products, hydro- gen and carbon monoxide, on the temperature and time on stream. ...
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... data are in good agreement with [23] that has studied alumina supported Ni, Co and Ni-Co catalysts with 9 wt% nominal metal content in the DRM reaction, and it was shown that higher activity and stability is exhibited by cobalt-rich cata- lysts. C) IK1 IK2 IK3 IK4 IK5 IK6 H 2 690 26 25 20 24 13 9 725 30 25 23 19 16 16 760 32 27 26 17 15 10 790 30 33 33 17 16 13 CO 690 37 44 29 24 20 14 725 43 44 33 23 22 18 760 44 41 35 23 22 13 790 43 41 38 22 22 16 After the DRM reaction, the surfaces of the glass fiber catalysts were studied by the TGA method. According to the obtained data, the amount of carbon on the surface is 0% for the sample IK 1 (Figure 11a), 0.51% for IK2 and 3.1% for IK6 (Figure 11b). ...
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The effect of molybdenum oxide as modifying additive on the catalytic properties of the catalyst NiO/Al2O3 obtained by the “solution combustion” method in the carbon dioxide conversion of methane was studied. It was established that the addition of 1 wt.% MoO3 to the 3 wt.% NiO/γ-Al2O3 composition leads to an increase in the specific surface area o...
Citations
... Besides preserving the catalytic performance of Ru for the Sabatier reaction, the silica nanofibers were easier to handle, recover, and reuse in comparison to the nanoscale powder-based catalysts [49]. Other works featured flexible glass fiber-supported Co-Ni catalysts for dry reforming of methane (DRM) and Co 3 O 4 nanowires deposited on stainless-steel wire meshes for steam reforming of ethanol [50,51]. Notably, these fiber-like supports (flexible glass fibers and stainless-steel wire meshes) presented large geometric surface area for excellent active catalytic site dispersion on the support surface, good mass, and heat transfer, along with low reactor pressure build-up, which offered more practicality relative to conventional particulate catalysts. ...
Catalytic methane (CH4) decomposition (CDM) offers a direct pathway for hydrogen (H2) gas production and valuable carbon nanotube (CNT) synthesis. However, the stability of this gas-to-solid reaction is hindered by limitations in CNT growth and reactor volume constraints. Departing beyond conventional nanopowder catalysts, we introduce basalt fiber-supported Ni/LTA catalysts that feature COx-free H2 generation and up to 3.7 times longer CDM reaction times, delivering an H2 production rate of 3.1 mol gNi⁻¹ h⁻¹ over 22 h at 500 °C, surpassing Ni/LTA nanopowder counterparts. The basalt fiber catalysts exhibit uniform and robust CNT growth, along with sustained and stable H2 generation lasting up to three times longer relative to traditional CDM catalysts that deactivate within 10 h as reported in the literature. Integration of the flexible basalt fiber catalysts into an H2-permeable LTA-Pd membrane reactor further enhances the reaction time by 36% and CH4 conversion by 40%, achieving up to 45% CH4 conversion over 27 h, surpassing expected equilibrium conversion rates. The excellent catalytic stability of the 10 wt% Ni/LTA basalt fiber catalyst is additionally showcased through multiple reduction-800 °C CDM reaction-CO2 regeneration cycles. This transformative study propels the development of functional catalyst materials, revolutionizing thermocatalytic processes.
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A basalt fiber-supported LTA zeolite-based nickel catalyst advances methane decomposition, yielding COx-free hydrogen, multi-wall carbon nanotubes, and extensive reaction time.
... It can reversibly store eight lithium ions according to the following conversion reaction (1). The number of studies that have been revealed that they are excellent electrocatalysts [6] as they are abundant, cheap, sensitive to the environment, and in some cases equal activity exactly like the noble metal-based catalyst. They have significant influences or can say critical effects of calcination temperature, pH, and fuel-to-oxidizer ratio on the morphology, phase composition, crystalline structure and OER function of the synthesized nanoparticles [2]. ...
... It also has a foam-like shape with pores that are micro-and nano-sized, that exhibit several beneficial characteristics for electrocatalytic applications. Due to their specific surface area, crystallinity, and porosity these nanoparticles have exceptional catalytic activity for the oxygen evolution reaction [2,6]. Vennela et al. (2019) has been studied the crystallite size of the Co3O4 nanoparticles. ...
Cobalt oxide nanoparticles are promising candidates for various kinds of practical application. The interest of researchers and scientists in these nanoparticles is due to their unique physical and chemical properties such as density, melting point, magnetic characteristics and band gap. The need to develop high performance and low-cost technologies for obtaining Co3O4 nanoparticles is a major reason in research in this area. The widespread commercial use of Co3O4 nanoparticles will open doors for numerous novel cost effective technologies, which are mostly dependent on the type of synthesis method and raw materials. A possible solution to this problem is to use Cobalt nitrates as a cost-effective precursor using the solution combustion method. Solution combustion synthesis method is one of the best candidate methods that have the potential for high performance and is also cost-effective. This review examines recent progress in the synthesis of Co3O4 nanoparticles by solution combustion method and underscores their significance across various fields, highlighting the need for further research and exploration of their multifaceted applications. In addition, the most recent advancements in the applications of Co3O4 nanoparticles in sensitive sensing, catalysis, supercapacitors/batteries and water treatment/pollutants removal are reviewed and described, focusing on current trends, challenges, and future outlooks.
... A very promising direction for the development of new catalytic technologies is the use of structured microfiber catalysts, in particular, glass fiber catalysts (GFCs) [9][10][11][12][13][14], which are distinguished by both high oxidation efficiency of organic compounds [14,15], and the possibility of creating catalytic cartridges that combine high efficiency of mass transfer and low hydraulic resistance [14,16]. ...
The article presents the results of the development and testing of a prototype device for the combustion of liquid fuels and the disposal of liquid toxic waste based on structured microfiber catalysts. The technology is based on a two-stage approach combining homogeneous and catalytic oxidation, which is carried out in a structured spiral cartridge with a modified glass fiber platinum-containing catalyst IC-12-S111. A prototype of a catalytic device with a thermal power of 18 kW was created and tested on a model fuel (diesel fuel). The optimal combustion mode is realized at a fuel consumption of 1.8 l/h, an air flow supplied to the burner - 12.3 st.m³/h and to the mixing zone in front of the catalytic block - 67 st.m³/h. At the same time, the air leaving the device contains practically no toxic impurities (CO, nitrogen and sulfur oxides). An important advantage of the proposed technology is its modularity, that is, the possibility of implementation in the form of low-power mobile devices, from which it is possible to form transportable and quickly deployable systems of any total capacity and a wide range of purposes.
... Использовалась Na-Si-стеклоткань марки КС-11-ЛА (88) (температурный интервал работы стеклоткани данной марки составляет 1000-1200 °С). Оксиды металлов Ni и Со наносились на поверхность стеклотканной матрицы методом "solution combustion" (SC), который является одним из вариантов самораспространяющегося высокотемпературного синтеза [30][31][32][33]. ...
... Рис. 8. Трехмерное изображение частиц катализатора 1.0-КС-0/100 (а), полученное на атомно-силовом микроскопе, и ПЭМ-снимок катализатора 0.8-КТ-60/40 (б) [26,33]. ...
В статье представлены оригинальные результаты по изучению образования и синтезауглеродных наноматериалов различного функционального назначения, полученныев Институте проблем горения: образование фуллерена в пламени; синтез углеродныхнанотрубок в пламени; синтез супергидрофобной углеродной поверхности в режимегорения; образование графеновыхслоев в пламенах; полная схема сажеобразования;СВС наноразмерных материалов; образование нитевидных кристаллов Al2O3 при СВСв системе Al-B2O3-Cr2O3; синтез наноразмерных катализаторов для углекислотнойконверсии метана в синтез-газ.
... Carbon deposition on Co-based catalysts is a severe problem in some reactions, such as FischereTropsch synthesis [30] and CO 2 reforming of CH 4 [31,32]. To examine the possible carbon deposition on the catalysts during RWGS reaction, post-reaction characterization experiments were performed. ...
The Co–CeO2 catalysts with different cobalt contents were prepared via co-precipitation method and used for reverse water–gas shift (RWGS: CO2 + H2 → CO + H2O) reaction. Characterizations of the catalysts were conducted by XRD, TPR, TPO, TEM and SEM. The results show that highly dispersed Co3O4 interacted with CeO2 is formed in 2% Co–CeO2 catalyst, and the catalyst shows excellent RWGS catalytic performance in terms of activity, selectivity and low carbon deposition. However, in the catalysts with high Co loading amount (≥5%), bulk Co3O4 with larger particle size is formed, which leads to obviously increased carbon deposition and by-product CH4 production during the reaction. These results suggest that highly dispersed Co, reduced from highly dispersed Co3O4 on CeO2, should be the key active component for RWGS reaction; while bulk Co with large particle size should be the key active component for methanation and carbon deposition.
Two series of supported Co-containing catalysts modified with La and Ce oxides were synthesized by solution combustion with different amounts of glycine. Their properties were compared with characteristics of unmodified Co catalyst and modified catalysts synthesized by impregnation in an excess of solution without glycine. XRD, TEM, UV-vis DRS and differential dissolution were employed to investigate the phase and chemical composition, morphology and localization of catalytically active particles in the support matrix. Their redox and catalytic properties were characterized using H2-TPR and kinetic experiments on the oxidation of butane. Specific surface area, particle size, chemical composition of the active component and its localization as well as the reducibility by hydrogen were shown to depend on the synthesis mode and amount of fuel additive (glycine). A higher catalytic activity of the samples obtained by solution combustion synthesis as compared to those synthesized by impregnation is caused by the enrichment of subsurface layers of the support with Co(II,III) cations in the composition of simple (Co3O4) and mixed (CoAl2O4) nanosized oxides, by an increase in specific surface area and a decrease in the particle size of the active component and promotor. It was shown that the amount of glycine has a stronger effect on the properties of the catalyst than its modification with lanthanum or cerium oxides.
The paper presents the results of a study of changes in the phase composition, magnetic and electrical properties of Co nanowires during thermal annealing in the temperature range 200–600 °C. The electrochemical deposition method was used as a method for producing Co nanostructures; polymer films with a pore diameter of 400 nm and a thickness of 12 μm were used as templates. In the course of the study, the dependences of the change in structural characteristics and phase composition on the annealing temperature were established. Three stages of evolution of the structural characteristics and phase transformations of nanostructures consisting of thermal annealing of defects and ordering of the crystal structure at low temperatures, the formation of the oxide phase and its domination in the structure with the subsequent phase transition from Co-C/Co-H to Co3O4 are determined. It is established that the appearance of the oxide phase leads to a change in the magnetic properties and the formation of the structure characteristic of paramagnets. In the course of the study of the conductive characteristics, it was found that an increase in the annealing temperature first leads to annealing of defects and an increase in conductivity, however, at a temperature of 600 °C, a deterioration in the conductive properties is observed.
