Gaukhar Ergazieva - Academia.edu (original) (raw)

Uploads

Papers by Gaukhar Ergazieva

Eurasian Chemico-Technological Journal, Jun 17, 2016

Chemical Bulletin of Kazakh National University, Jan 21, 2022

Казахский национальный университет им. аль-Фараби, Центр физикохимических методов исследований и ... more Казахский национальный университет им. аль-Фараби, Центр физикохимических методов исследований и анализа, Алматы, Казахстан

Eurasian Chemico-Technological Journal

The effect of modifying additive (La2О3) on the activity of Ni-Co oxides was studied for the dry ... more The effect of modifying additive (La2О3) on the activity of Ni-Co oxides was studied for the dry reforming of methane (DRM). The catalysts were prepared by impregnation of the granulated diatomite (D) and characterized by SEM, EDX, H2-TPR, XRD, and AES. It is shown that the addition of 1.5 wt.% La2O3 into the Ni-Co/D composition leads to an increase in the activity of the catalyst, providing a methane conversion that is close under thermodynamic equilibrium conditions in the temperature range of 700‒850 °С. The highest activity is achieved at T = 850 °C, the conversion of methane is 96%, and carbon dioxide is 92%. The addition of lanthanum oxide to the Ni-Co/D composition led to an increase in catalyst stability; after testing in the DRM reaction for 360 min, the deactivation coefficient for methane was 3.4%, and for carbon dioxide 2.5%. While significant deactivation is observed for Ni-Co/D, the deactivation coefficient for methane is 19%, and for carbon dioxide 36%. Many character...

Eurasian Chemico-Technological Journal, 2018

The catalytic activity of carriers: θ‒Al2O3, γ‒Al2O3, 5A, 4A, 3A and 13X and the oxides of metals... more The catalytic activity of carriers: θ‒Al2O3, γ‒Al2O3, 5A, 4A, 3A and 13X and the oxides of metals of variable valency ‒ NiO, La2O3, CuO, MoO3, MgO, V2O5, WO3, CoO, Cr2O3, ZnO, ZrO2, CeO2, Fe2O3, supported on the effective carrier γ‒Al2O3 by the method of capillary impregnation of the support with solutions of nitric salts of metals were investigated in the process of carbon dioxide conversion of methane (DRM). The optimal technological regimes for the process were: the reaction temperature -800 °C, the space velocity of the initial reactants ‒ 1500 h-1 with a methane to carbon dioxide ratio equal to 1. It was found that among the studied catalysts the highest activity is shown by the NiO/γ‒Al2O3 catalyst, where the yields of hydrogen and carbon monoxide reaches 45.4 and 42.4% by volume, respectively, when methane conversion is 89%. The XRF method showed that the content of alumina and nickel oxide after the reaction remained unchanged at 96.7 and 3.0%, respectively. Scanning electro...

Chemical Bulletin of Kazakh National University

This work is devoted to the study of the activity of monometallic (Fe/Al2O3) and bimetallic (Fe-M... more This work is devoted to the study of the activity of monometallic (Fe/Al2O3) and bimetallic (Fe-Mo/Al2O3) catalysts supported to carrier γ- Al2O3. It has been discovered that the bimetallic catalyst is more active than the monometallic catalyst in the methane decomposition reaction. The results of the influence of molybdenum oxide on the activity of Fe/Al2O3 catalyst in the methane decomposition reaction in the temperature range 500-850°C have been obtained. It has been determined that the addition of molybdenum oxide in the amount of 5 wt. % of the iron catalyst composition leads to an increase in the catalytic activity of the sample in the reaction of methanedecomposition to hydrogen at relatively low temperatures. Compared to Fe/Al2O3 on the FeMo/Al2O3 catalyst at a reaction temperature of 750°C, methane conversionincreases from 8% to 98%, hydrogen yield from 5% to 57%. The increased field of activity Fe-Mo/Al2O3catalyst in the decomposition of methane to hydrogen compared to Fe/...

Chemical Engineering & Technology, 2021

Bulletin of Chemical Reaction Engineering & Catalysis, 2021

This article discusses the decomposition of methane in the temperature range 550–800 °C on low-pe... more This article discusses the decomposition of methane in the temperature range 550–800 °C on low-percentage monometallic (Ni/g-Al2O3, Co/g-Al2O3) and bimetallic (Ni-Co/g-Al2O3) catalysts. It is shown that the bimetallic catalyst is more active in the decomposition of methane to hydrogen than monometallic ones. At a reaction temperature of 600 °C, the highest methane conversion is 81%, and the highest hydrogen yield of 51% is formed on Ni-Co/g-Al2O3. A complex of physicochemical methods (Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR-H2), etc.) established that the addition of cobalt oxide to the composition of Ni/g-Al2O3 leads to the formation of surface bimetallic Ni-Co alloys, while the dispersion of particles increases and the reducibility of the catalyst is facilitated, which provides an increase in the concentration of metal particles - active centers, which can be the reason for an increase in the catalytic properties of a bi...

Theoretical and Experimental Chemistry, 2019

The effect of molybdenum oxide as modifying additive on the catalytic properties of the catalyst ... more The effect of molybdenum oxide as modifying additive on the catalytic properties of the catalyst NiO/Al 2 O 3 obtained by the "solution combustion" method in the carbon dioxide conversion of methane was studied. It was established that the addition of 1 wt.% MoO 3 to the 3 wt.% NiO/g-Al 2 O 3 composition leads to an increase in the specific surface area of the catalyst and the mobility of the surface oxygen, resulting in increased catalyst activity and resistance to carbonization.

Chemical Bulletin of Kazakh National University, 2014

Chemical Papers, 2021

Ni-Co/γ-Al2O3 bimetallic catalysts were synthesized by capillary impregnation (CI) and solution c... more Ni-Co/γ-Al2O3 bimetallic catalysts were synthesized by capillary impregnation (CI) and solution combustion methods (SC). Catalysts tested in dry methane reforming (DRM), characterized by XRD, H2-TPR, SEM, small-angle X-ray scattering. Preparation method plays an important role in regulating the textural and morphological properties of catalysts and provides a difference in indices of their activity. Synthesis of Ni-Co/γ-Al2O3 by SC in comparison with CI method leads to formation of solid solution of NiCo2O4 with a CSR size of 21 nm, increases the proportion of metal ions (Ni, Co) reduced at temperatures of 400–700 °C, uniform distribution of nanosized particles of active phase on carrier surface. At comparatively low reaction temperature (600 °C) on sample synthesized by SC, degree of methane conversion is higher compared to sample prepared by CI, XCH4-69%, XCH4-65%, respectively. SC provides an efficient way to develop an active catalyst for DRM at low temperatures (600–750 °C).

Comptes Rendus Chimie, 2017

The purpose of this work was to investigate biomass-derived ethanol dehydrogenation into acetalde... more The purpose of this work was to investigate biomass-derived ethanol dehydrogenation into acetaldehyde using several mono-and multicomponent (CuO, ZnO and Cr 2 O 3)-containing catalysts supported on industrial size Al 2 O 3 beads. The catalysts, prepared with either solution combustion or incipient wetness method, were characterized by using various physico-chemical methods, such as EDXA, SEM-EDXA, TEM, XRD, XPS, pyridine adsorption desorption FTIR, and z-potential measurements. The results revealed that the multicomponent catalysts exhibited superior activity compared to the metal oxide catalysts containing only one metal oxide. In addition, the most selective catalyst towards acetaldehyde formation, with 50% selectivity at 55% conversion of ethanol at 300 C and WHSV 1 h À1 was CuOeCr 2 O 3 /Al 2 O 3 prepared by using the solution combustion method, indicating that this inexpensive and rapid catalyst preparation method is promising for other applications.