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Item Open Access Abstract Book of The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08)The INESS 2020 topics covered the following and related areas: advanced nanomaterials for energy application, advanced energy storage, conversion and saving systems, materials for electrochemical sensor and electroanalytical applications, catalysis and fuel cells, battery monitoring and management systems, battery safety and utilization, development of electric vehicles and stationary energy storage. The scientists and students from Japan, Korea, France, Germany, China, Russia, Canada, UAE, UK, Turkey and Kazakhstan reviewed and discussed the recent progress and problems in materials science, nanotechnologies, ecology, renewable energy, energy storage systems and modeling methods in these fields.Item Open Access Adsorption arsenite from aqueous solutions by Cu/CuO loaded composite track-etched membranes(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Mashentseva, Anastassiya; Khassen, Tomiris; Zhumazhanova, Ainash; Zheltov, Dmitriy; Russakova, Alyona; Rakisheva, Saniya; Altynbayeva, Liliya; Aimanova, NurgulimNanoscale structures of copper and its oxides are widely used in heterogeneous catalysis and demonstrate improved properties compared to bulk analogues [1]. Previously, we demonstrated the high potential of composite track-etched membranes with copper microtubules (MTs) as effective catalysts for pnitrophenol hydrogenation and the Mannich reaction [2]. In addition, efficient sorption of ions of heavy metals, such as As, Pb, Cd, Ni, etc. is a promising application of CuO NPs [3]. The composites with the internal pore diameter of 280 nm and the copper microtubules wall thickness of 75 nm were obtained by chemical template synthesis in nano-channels of track-etched PET membranes. Upon the analysis of the data on the phase composition and degree of crystallinity of microtubules before and after annealing, it was found that the complete conversion of copper to copper(II) oxide is possible only at temperatures of 140 °C and higher, and 100% tenorite phase is formed after 10 hours of annealing at 140°C. The composites annealed at 140 °C were also tested in terms of their arsenic (III) ions sorption capacities in the flow mode. For the unannealed sample, the effect of flow-rate on sorption activity was studied and the optimal value of 10 mL/min was established. It was shown that the sorption capacity of composite membranes increases by 48.7% compared to the initial sample at 10 h of annealing and then decreases by 24% with an increase in the annealing time (24 h). Successfully combining mechanical strength, the possibility of repeated use, low cost and ease of production, such Cu/CuO/PET membrane composites can be considered as promising materials for sorption of arsenic ions from aqueous solutions.Item Open Access Advanced Functional Nanomaterials for Photocatalytic Water Splitting(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Nuraje, NurxatThrough mimicking Nature, unique assembled nanostructures can be designed and fabricated to improve certain properties of materials and device performance for targeted applications. In this presentation, we discuss the synthesis, and characterization of novel bio-inspired and biomimetic functional nanomaterials, and their properties. At the same time, we discuss how to apply them to investigate fundamental science in photocatalytic water splitting via creating their hierarchical nanostructured materials. In brief, this talk will focus on the following topics: (a) synthesis of bio-inspired functional nanomaterials; (b) fabrication of unique nanoarchitectures to better understand fundamental science; and (c) Applying these unique nanomaterials and nanostructures to resolve the scientific problems in Photocatalytic Water Splitting.Item Open Access Ag:TiO2 plasmonic nanocomposite films obtained by RF magnetron co-sputtering(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Mukhametkarimov, Yerzhan; Mikhailova, Svetlana; Prikhodko, Oleg; Dauitkhan, Kuanysh; Puzikova, Darya; Doseke, UlantaiIt is known that TiO2 is a wide-gap semiconductor, which due to its low cost and photocatalytic properties has found great application in purification of water and organic pollution, as well as solar energy [1]. To expand an application area, various methods of functionalization and alloying of TiO2 with various metallic and nonmetallic impurities and particles are used. One of these ways is usage of plasmon nanoparticles, like Au and Ag, to increase the absorption region in the visible range [2]. In this work, plasmon nanocomposite films of Ag:TiO2 were obtained by RF magnetron co-sputtering [3]. It was revealed that the films consist of an amorphous TiO2 matrix and isolated silver nanoparticles with 3-5 nm diameter. The optical absorption spectra of Ag:TiO2 nanocomposite films are characterized by local maxima at 465-480 nm corresponding to light scattering plasmon resonance (LSPR). Photoelectrochemical studies of Ag:TiO2 nanocomposite films in 0.1 M Na2SO4 under illumination with 465 nm light showed that silver nanoparticles presence in the matrix increases the photoconductivity. The quantum yield for Ag:TiO2 composite films increases significantly, while for a pure TiO2 film this value does not exceed 0.5%. In addition, work was carried out related to the degradation of the methylene blue dye (MB dye) under the direct action of solar radiation, from which it follows that the presence of silver nanoparticles in the TiO2 matrix increases the rate of decoloration of the aqueous solution with MB dye. Thus, the obtained TiO2:Ag nanocomposite films are a promising material for use in nonlinear optics, electronics, electrooptics, photocatalytic and antireflection coatings and photoconverters, as well as in biomedicine as antibacterial coatings.Item Open Access All-Purpose Electrode Design of Flexible Conductive Scaffold toward High-Permanence Li-S Batteries(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Zhang, Yongguang; He, Yusen; Zhao, Yan; Bakenov, ZhumabayThe main obstacles that hinder the development of efficient lithium sulfur (Li-S) battery are the polysulfide shuttling effect in sulfur cathode and the uncontrollable growth of dendritic Li in the anode. Herein, we report an all-purpose flexible electrode that can be served both in sulfur cathode and Li metal anode, and meanwhile the application in wearable and portable storage electronic devices is discussed. The flexible electrode consists of a bimetallic CoNi nanoparticles embedded porous conductive scaffold with multiple Co/Ni-N active sites (CoNi@PNCFs). Both experimental and theoretical analysis show that, when used as the cathode, the CoNi and Co/Ni-N active sites implanted on the porous CoNi@PNCFs significantly promot the chemical immobilization towards soluble lithium polysulfides and its rapid conversion into insoluble Li2S, and therefore effectively mitigates polysulfide shuttling effect. Meanwhile, the 3D matrix constructed with porous carbonous skeleton and multiple active centers successfully induce homogenous Li growth, realizing a dendrite-free Li metal anode. The Li-S battery, assembled with S/CoNi@PNCFs cathode and Li/CoNi@PNCFs anode, achieve a high reversible specific capacity of 785 mAh g-1 and long cycle performance at 5 C (capacity fading rate of 0.016 % over 1500 cycles).Item Open Access Amorphous silicon dioxide as an anode material for li-ion batteries(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Askaruly, Kydyr; Azat, Seitkhan; Ulan, Zhantikeyev; Yeleuov, MukhtarIn recent decades, progress in Li-ion batteries (LIBs) has grown dramatically. In 2016, about 6.4 billion cells were sold of LIBs and this is equivalent to 90 GWh [1]. even the Nobel Prize in Chemistry in 2019 was awarded to John Goodenough (USA), Stanley Whittingham (Great Britain) and Akira Yoshino (Japan) for the development of lithium-ion batteries. But work on improving the Li-ion batteries is still ongoing. SiO2 is one of the most widely used materials on earth. SiO2 is one of the most widely used materials on earth and is uses in the fields of medicine, cosmetics, agroindustry, electronics [2,3], and has also begun research on the use of SiO2 as an anode material in lithium-ion batteries [4]. It has a high theoretical capacity (1965 mAh•g-1) [5]. SiO2 obtained by us is amorphous and the source is rice husk (RH) from Kazakhstan (Kyzylorda region). Material synthesis is divided into two stages. Stage 1 includes washing pre-treatment by HCl and calcination at 600°C (SiO2-1). Stage 2 includes purification by dissolving in NaOH and extraction pure (SiO2-2) by adding HCl and washing by distilled water. The use of 1 stage material as an anode material in lithium-ion batteries has shown good stability. Microstructure of SiO2-1 and SiO2-2 differs from each other. SiO2-2 at the beginning showed good stability, but from the 10th cycle, it began to lose capacity.Item Open Access Analysis of the dependence of the structural parameters of membranes based on NOA and anode current on the parameters of the production process(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Batalova, M.S.; Alpysbayeva, B.E.; Korobova, N.E.Among the porous membranes, PAOA-based membranes, formed by the method of electrochemical anodizing of aluminum foil, are of the greatest interest. Membranes obtained by electrochemical anodization are highly ordered structures with parallel vertical pores [1]. The unique porous structure, the parameters (diameter, length and distance between adjacent pores) of which can be varied during the synthesis process allows the use of films of porous aluminum oxide as inorganic membranes, templating material for the synthesis of nanowires or nanotubes with a controlled diameter and high geometric anisotropy, as well as 2D photonic crystals and biosensors [2,3]. Aluminum foil (99.999%) with a thickness of 0.5 mm was used as the starting material for the synthesis of films of porous aluminum oxide. Oxide layer formed on the foil surface was removed by electrochemical polishing of aluminum in a mixture of 40g CrO3 + 210 ml H3PO4 (concentrated acid) + 45 ml H2O at a temperature of 80°C. The membranes based on porous alumina were obtained by a two-stage anodizing process in 0.4 M oxalic acid at a temperature of 4–19 ° C. With an increase in the magnitude of the voltage, the thickness of the porous film, which grows in the same time, increases; the growth rate of the film grows sublinearly. With increasing voltage value, the initial value of the anode current also increases. The anode current in the anodization process gradually decreases, which, as already noted, indicates the beginning of pore formation and further stabilization of the anode current occurs when the pores grow deep into the oxide film. According to the data obtained on the dependence of the anode current on the time of the anodization process, it can be concluded that the maximum current value at room temperature is higher than at low temperature, and this can be traced for all voltage values.Item Open Access Bulk and Interfacial Defect Passivation for High Perofrmance Perovskite Solar Cells(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Aidarkhanov, Damir; Ren, Zhiwei; Lim, Chang-Keun; Yelzhanova, Zhuldyz; Nigmetova, Gaukhar; Baptayev, Bakhytzhan; Balanay, Mannix; Surya, Charles; Prasad, Paras N.; Ng, AnnieNowadays, perovkite materials are considered to be the most promising absorber media for the third generation photovoltaics. Outstanding material properties allowed perovskite solar cells’ power conversion efficiency values to exceed 25% in ten years, demonstrating the highest efficiency increase rate among all the available photovoltaic technologies. Despite such progress technology commercialization requires further device performance enhancement. Here, we report a performance increase strategy implying passivation of both bulk and interfacial defect states. To passivate the bulk defects an organic cross linker, 2,2′-(ethylenedioxy)bis (ethylammonium iodide) (GAI), was added into the mixed perovskite absorber layer. Different experimental techniques reveal that optimized amount of GAI, indeed, passivates defect states via cross-linking perovskite grains, while excess amount of cross-linker material deteriorates device performance due to generation of new defects and poor conductivity of the organic additive. The interfacial defects were passivated by interface engineering technique, namely, via application of a composed electron transport layer (ETL) consisting of quantum dot (QD) SnO2, nanoparticle (NP) SnO2 and a passivation layers based on PMMA:PCBM. It was demonstrated that a single-layer ETL made of QD SnO2 or NP SnO2 causes devices to show I-V hysteresis, while application of a triple-layer ETL effectively suppresses the hysteresis due to the optimization of ETL/perovskite interface. Thus, the cumulative effect of both applied techniques allowed to increase device’ power conversion efficiency, almost completely remove hysteresis and improve the solar cell stability.Item Open Access C-SiC and Si-SiC thin film systems as the anodes for LIBs(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Mukanova, Aliya; Mukhan, Orynbassar; Myronov, Maksym; Bakenov, ZhumabayThe miniaturization of the devices requires the miniaturization of energy storage systems. Lithium-ion batteries can provide the highest energy at smaller size and ligher weight among other energy systems. The present work reports the study of the development of new types of anodes – carbon film deposited on SiC thin film and Si thin film on SiC produced by chemical vapor deposition (CVD) method. The SiO2/MgF2/Al/Ti omics contacts were deposited by magnetron sputtering and annealed at 600 OC and served as the anode current collectors. The studies were accompanied by microscopic investigation and structural characterization.The the electrochemical results and characterization details will be detailed at the conference.Item Open Access Composite PAAm-based hydrogel electrolyte for hybrid aqueous (Zn-Li-ion) battery(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Zhanadilov, Orynbay; Mentbayeva, Almagul; Beisbayeva, Zhanna; Amze, Magzhan; Bakenov, ZhumabayHybrid aqueous rechargeable batteries are very attractive alternative to conventional rechargeable lithium ion batteries for stationary application because of production and usage safety, reduced production cost and environmental friendliness. Previously aqueous rechargeable batteries with Zn/LiCl-ZnCl2/LiFePO4 system with liquid electrolyte has been reported [1]. The system performed a high rate capability up to 60 C with the average operation voltage 1.2 V and cycling performance with a capacity retention of 80 % over 400 cycles at 6 C. However, there are several drawbacks including water decomposition and zinc dendrite formation hindering the commercialization [1]. The present study aimed to develop a PAAm-based hydrogel electrolyte with inclusion of montmorillonite and halloysite clay nanoparticles for hybrid aqueous rechargeable zinc/lithium ion batteries to overcome above mentioned problems. Polyacrylamide hydrogel was chosen because of its high ionic conductivity, high water content and simple fabrication method in which cross-linking degree, thickness, etc. were optimized. Inclusion of clay could improve mechanical stability of hydrogel electrolyte, prevent water decomposition and dendrite formation. All tests performed in Zn/LiFePO4 cell operating in an optimized LiCl/ZnCl2 aqueous electrolyte based hydrogel.Item Open Access Conformal coating of LTO/PAN for high performance Si nano-composite anodes(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Mukhan, Orynbassar; Nurpeissova, Arailym; Bakenov, ZhumabaySilicon is a potentially promising anode material for the next-generation energy storage devices owing to advantages as low cost, low toxicity and high specific capacity. However, there are several disadvantages of the silicon that shorten the life time of the battery such as instability of SEI layer, low electrical conductivity and volume change [1]. Huge volume expansion (>300%) during the lithiation/delithiation processes, which results in the pulverization of Si particles and fast capacity loss of the anode material, is considered as a major problem [2]. To be implemented commercially Si nanoparticles should exhibit high-power and low volume change. So far, there have been no credible Si-based materials reported satisfying all of these requirements [3]. Here, we report modified Si nanoparticles co-coated with Li4Ti5O12 and cyclized polyacrylonitrile targeted to enhance the conductivity and tolerance to volume change. The synergistic effect from both coating provide the Si electrode with good conductivity and better performance. Synthesized Si/LTO/cPAN composites were characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM) to identify the structure and morphology of composites.Item Open Access Controlled Oxygen Redox for Excellent Power Capability in Layered Sodium‐Based Compounds(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Kim, Hee Jae; Konarov, Aishuak; Myung, Seung-TaekRecently, anionic oxygen redox (O2−/1−) become a main research subject for realizing high power capability [1]. Unfortunately, although the delivered capacity obtained from the transition-metal redox and oxygen redox is one of highest among sodium cathodes, the system suffers from not only serious capacity fading but also poor rate capability because of the sluggish kinetics of the oxygen redox [2]. To come up with this drawback, cobalt substitution in layered sodium-based compounds is conducted to achieve a high-rate of oxygen redox. The rationally designed Na0.6[Mg0.2Mn0.6Co0.2]O2 exhibits outstanding electrode performance, delivering a discharge capacity of 214 mAh g−1 (26 mA g−1) with capacity retention of 87% after 100 cycles. High rate performance is also achieved at 7C (1.82 A g−1) with a capacity of 107 mAh g−1. Surprisingly, the Na0.6[Mg0.2Mn0.6Co0.2]O2 compound is able to deliver capacity for 1000 cycles at 5C (at 1.3 A g−1), retaining 72% of its initial capacity of 108 mAh g−1. X-ray absorption spectroscopy analysis of the O K-edge indicates the oxygen-redox species (O2−/1−) is active during cycling. First-principles calculations show that the addition of Co reduces the bandgap energy from ≈2.65 to ≈0.61 eV and that overlapping of the Co 3d and O 2p orbitals facilitates facile electron transfer [3], enabling the long-term reversibility of the oxygen redox, even at high rates. To the best of the authors’ knowledge, this is the first report on high-rate oxygen redox in sodium-based cathode materials, and it is believed that the findings will open a new pathway for the use of oxygen-redox-based materials for sodium-ion batteries.Item Open Access Dynamic Chemical Passivation of Absorber Layer Trap States and its Real-time Effect on the Device Performance in Back-Contact Perovskite Solar Cells(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Jumabekov, Askhat N.Hybrid organic-inorganic perovskites have been identified as one of the most promising classes of materials for photovoltaic and optoelectronic applications, due to their excellent electronic and optical properties, combined with their ease of fabrication. The efficiency of perovskite solar cells (PSCs) has increased at a remarkably fast pace, with the current maximum certified power conversion efficiency (PCE) reaching 25.2%. Conventional solid-state hybrid organic-inorganic perovskite-based solar cells have a sandwich type structure in which the perovskite absorber layer is positioned between bottom and top electrodes, typically a transparent conducting oxide (TCO) layer on glass, and an evaporated thin layer of gold or silver, respectively. Such an architecture for PCSs allows illumination of the cells only from the TCO side. Alternatively, the back-contact architecture offers the possibility of positioning both electrodes on one side of the absorber layer and shining light directly on the photoactive layer [1, 2]. This helps to avoid the occurrence of transmission losses caused by the charge collecting TCO electrode in the conventional sandwich structure for PSCs, and may have some potential application in constructing four or two terminal tandem solar cell devices. The back-contacted device architecture is also useful for conducting fundamental studies as it has an exposed photoactive area, permitting in situ measurements on the effects of chemical treatment, passivation and annealing. I will present a successful application of back-contact PSCs in studying the dynamic effect of a chemical passivation of the perovskite absorber layer and it is real-time influence on the device performance.Item Open Access Effect of Ag impurity on the optical properties of GST225 thin films(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Turmanova, Kundyz; Prikhodko, Oleg; Ismailova, Guzal; Zhakypov, Alibek; Maksimova, Suyumbika; Tolepov, ZhandosIntensive research is currently underway to develop materials for the optical recording of information based on a glass-crystal phase transition. Promising materials for this direction are thin films of chalcogenide semiconductors based on the Ge-Sb-Te system. To improve the parameters of recording and rewriting information, the speed of the phase transition, the number of write-erase cycles used the impurity modification with metals such as Ag, In and Bi. It was found that Ag atoms act as nucleation centers that can reduce the activation energy of crystallization and increase the crystallization rate of the film, thereby erasing the PCRAM erasure rate [1]. The report presents the results of the influence of silver impurity and size effect on the optical properties of Ge2Sb2Te5 (GST225) films. Nanosized films GST225 modified by Ag were obtained by ion-plasma RF magnetron sputtering of a combined target from GST225 and Ag in an Ar atmosphere. The used power of the RF generator was selected in such a way as to produce GST225 films with an amorphous structure. Crystallization was performed by thermal annealing at 300°C. The films’ thickness range ~50-150 nm and was determined on the Quanta 3D 200i SEM. The concentration of silver impurities in the films was 5.0 and 9.7 at. %. The optical properties of studied films deposited on glass substrates were investigated using Shimadzu UV2000. It was found that the spectral dependences of the transmission coefficients T(λ), absorption α(hν), and the optical band gap Eg depend both on the concentration of Ag in the films and on their thickness. It was found that for amorphous and crystalline GST225 films in the range of the studied Ag impurity concentrations and their thicknesses, the quadratic law of light absorption is observed, which indicates the realization of indirect allowed optical transitions. Modification of amorphous and crystalline GST225 films with silver impurities leads to a substantial decrease in the optical band gap. At a fixed concentration of Ag impurity in GST225 films in the amorphous and crystalline state, with a decrease in their thickness to 50 nm, a significant decrease in Eg is also observed. Thus, the modification of GST225 films with an Ag impurity leads to significant changes in their structure and optical properties.Item Open Access Effect of annealing on the optical properties of TiO2 films(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Prikhodko, Oleg; Mikhailova, Svetlana; Mukhametkarimov, Yerzhan; Maksimova, Suyumbika; Dauitkhan, Kuanysh; Doseke, UlantaiIn this work, TiO2 films, which were obtained by ion-plasma high-frequency magnetron sputtering of a polycrystalline rutile target in an argon atmosphere at 1 Pa pressure were studied. The TiO2 films were annealed for 1 hour in air in the temperature range from 100 °C to 400 °C with 100 °C increment. It was found that the TiO2 films have high transparency, which remains almost unchanged during annealing. The fundamental absorption edge of the films, which is located from 320 to 380 nm, also changes slightly with increasing annealing temperature up to 400 °C. The refractive index n(λ) of the films decreases with incident radiation increasing and, as a result, TiO2 films are characterized by normal dispersion. With increasing annealing temperature, the refractive index n in the long-wavelength region of the spectrum increase in comparison with those in films without annealing. When comparing the calculated values of n(λ) with theoretical values, one can see that in the short-wavelength region of the spectrum, the dependences n(λ) coincide, while discrepancies are observed with wavelength increasing. This may be due to the structural features of the films, which depend on their thickness. In a literature, the refractive index of titanium dioxide was measured for samples with ~ 1-2 μm thickness, while in this work the films with ~ 270 nm thickness were studied. From the calculated n(λ), we can conclude that for TiO2 films the optical properties are stable up to a temperature of 600 °C. It was found that the absorption laws are equally well satisfied for the studied TiO2 films before and after annealing. This means that for TiO2 films before and after annealing at 400 °C, the realization of direct and indirect optical transitions upon absorption of light quanta is equally probable. Optical band gap of the films annealed at 400 °C, determined from the quadratic absorption law, was ~ 3.01 eV, which is typical for TiO2 films with a rutile structure. This Eg is significantly less than the value obtained using the law with γ = 1/2, which corresponds to the allowed direct-gap optical transitions.Item Open Access The Effect of Chemical Activating Agents on the Morphology and Structure of Bio-Derived Activated Carbon(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Issatayev, Nurbolat; Nurpeissova, Arailym; Kalimuldina, Gulnur; Bakenov, ZhumabayRecently, activated carbon (AC) has attracted more and more attention since it exhibits various properties, including operated pore size and morphology, strong mechanical and physico-chemical stability, good absorption capacity and crucially important, large surface area. This makes it an ideal material for use in energy storage, metal recovery, air purification, medical wastewater treatment, water purification, gas storage, and removal of caffeine. In this study, ACs were fabricated by single-stage carbonization and activation of a carbon precursor with four different chemical activating agents such as potassium hydroxide (KOH), zinc chloride (ZnCl2), phosphoric acid (H3PO4) and sulfuric acid (H2SO4), respectively. Agar-agar was used as a bio-derived carbon precursor due to its high carbon content and the lack of any traces of heavy metals. The effect of the activating agents and the weight ratio of activating reagents / precursor as well as the nature of the precursor have been examined and discussed. The morphological and textural properties of ACs were investigated using an electron scanning microscope (SEM), X-ray diffraction (XRD), Raman and FTIR techniques.Item Open Access Effect of copper sulfate concentration in growth solution on photocatalytic properties of ZnO/CuO nanostructures(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Kedruk, Y.Y.; Gritsenko, L.V.; Abdullin, Kh.A.; Cicero, G.Metal oxide semiconductors are the most suitable materials used for photocatalytic processes in industry and the environment (in particular, they are involved in wastewater decontamination processes). Semiconductors are relatively inexpensive, safe for health, chemically stable, and have high photosensitivity [1, 2]. One of the most challenging tasks at present is to improve the photocatalytic activity of photocatalysts for practical applications in the visible range, namely, high energy transfer efficiency, non-toxicity and low cost. The main efforts in the field of photocatalysis are devoted to the modification of existing photocatalysts to increase their photocatalytic characteristics [3]. In this work, semiconductor composites of copper (II) oxide and zinc oxide (ZnO/CuO) were synthesized using a low-cost method. To study the effect of the concentration of copper sulfate in the growth solution on the photocatalytic properties ZnO/CuO nanocomposites were synthesized by a low-temperature hydrothermal method. The aqueous solution contained copper sulfate, zinc chloride, and sodium hydroxide. A series of samples with different concentrations of copper sulfate (0.7 mmol - 2.0 mmol) was considered. The results of studying of the synthesized samples by electron microscopy showed that the obtained ZnO/CuO nanocomposites consist of thin filamentary ZnO rods with CuO nanoparticles attached to them. It was noted that an increase in the copper sulfate concentration in the growth solution to 2.0 mmol with the remaining parameters unchanged leads to an insignificant change in morphology: the volume of flocculent structures and the amount of CuO nanoparticles increase. Samples of the RhB solution for measuring of the optical density spectra were carried out every 30 minutes for 150 minutes. It should be noted, that with the used the same parameters for the ZnO/CuO powders synthesis, an increase in the amount of CuO nanoparticles in ZnO/CuO composites leads to a decrease in their photocatalytic activity which appears to be due to dimming effect at UV exposition.Item Open Access Effective penetration depth of optical radiation in nanoscaled modified Ge2Sb2Te5 films(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Zhakypov, Alibek; Maksimova, Suyumbika; Prikhodko, Oleg; Ismailova, Guzal; Turmanova, Kundyz; Tolepov, ZhandosThin films of Ge-Sb-Te (GST) chalcogenide semiconductor materials and, in particular, Ge2Sb2Te5 composition, are used for creation of optical information carrier on the basis of a “glass-crystal” reversed phase transition. To improve information recording parameters, GST compositions are modified with an admixture of metal. In this case, the impurity must be isovalent and isomorphic with one of the components of the matrix. For the Ge2Sb2Te5 composition, one of these impurities is silver. The report presents the results of study of the optical properties of nanoscale amorphous and crystalline Ge2Sb2Te5 films modified with Ag, and spectral dependence of the effective depth of penetration of optical radiation into these materials deff (λ) are also presented. Amorphous Ge2Sb2Te5 films modified with silver (a-Ge2Sb2Te5) were obtained by ion-plasma RF (13.56 MHz) magnetron sputtering of a combined target from a polycrystalline of Ge2Sb2Te5 and Ag. The film thickness l was ~ 100 nm, and the silver impurity concentration in the films was reached 5 at.%. Crystallization of the amorphous films was carried out by thermal heating. The phase state of the film structure was monitored using Raman spectroscopy. The optical properties of the films (transmission spectra T(λ) and reflection R(λ) of light) were recorded on a Shimadzu UV2000 spectrophotometer in the range from 300 to 1100 nm. The spectral characteristics of light absorption α(λ) of the films were calculated from the expression α(λ) = -1/l·{ln[T(λ)/(1-R(λ)2]}. The effective penetration depth deff (λ) of the optical radiation for the films was determined from the relation deff (λ) = 1/α(λ). Analysis of the spectral dependences deff (λ) for amorphous and crystalline Ge2Sb2Te5films showed that the effective depth of light penetration decreases significantly with increasing impurity concentration. In с-Ge2Sb2Te5crystalline films, it is much smaller than in amorphous a-Ge2Sb2Te5 films. The obtained results are important for creating optical information carriers based on nanoscaled Ge2Sb2Te5films using radiation from lasers with different wavelength.Item Open Access Electrospun 3D structured carbon current collector for Li/S batteries(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Yerkinbekova, Yerkezhan; Kalybekkyzy, Sandugash; Mentbayeva, Almagul; Baikalov, Nurzhan; Kahraman, Memet Vezir; Bakenov, ZhumabayLight weight carbon nanofibers (CNF) fabricated by a simple electrospinning method and used as a 3D structured current collector for a sulfur cathode. Along with a light weight, this 3D current collector allowed us to accommodate a higher amount of sulfur composite, which led to a remarkable increase of the electrode capacity from 200 to 500 mAh g-1 of the electrode including the mass of the current collector. Varying the electrospinning solution concentration enabled obtaining carbonized nanofibers of uniform structure and controllable diameter from several hundred nanometers to several micrometers. The electrochemical performance of the cathode deposited on carbonized PAN nanofibers at 800 ◦C was investigated. An initial specific capacity of 1620 mAh g−1 was achieved with a carbonized PAN nanofiber (cPAN) current collector. It exhibited stable cycling over 100 cycles maintaining a reversible capacity of 1104 mAh g−1 at the 100th cycle, while the same composite on the Al foil delivered only 872 mAh g−1. At the same time, 3D structured CNFs with a highly developed surface have a very low areal density of 0.85 mg cm−2 (thickness of ~25 μm), which is lower for almost ten times than the commercial Al current collector with the same thickness (7.33 mg cm−2 ).Item Open Access Enhanced gas sensing properties of IZO thin films using SILAR(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Soltabayev, Baktiyar; Mentbayeva, Almagul; Çağırtekin, Ali Orkun; Acar, SelimIn the last decades, resistive gas sensors based on semiconductor oxides have been the topic of interest for a long time due to their high sensitivity to both oxidizing and reducing gases. These sensors meet the main market requirements such as low cost, small size, and easy maintenance. Currently, much attention has been attracted to finding an effective method to improve the nanomaterials’ sensing ability and selectivity. Sensor devices based on semiconductor oxide like ZnO are important sensing material for detection of hazardous gases [1]. ZnO is the most extensively applied as a gas sensing material, since it has remarkable characteristics necessary for an ideal metal oxide gas sensor such as wide band-gap energy (Eg=3.37 eV) and high binding energy (Ee=60 meV) [2]. Several approaches have been applied to improve gas sensing performance, for instance, morphological changes by doping metal. Especially, indium (In) significantly influences the electrical, chemical, structural, and gas sensing properties of ZnO. In the present work, the effect of In doping on the various properties of ZnO was investigated. The pure ZnO and indium doped ZnO thin films have been synthesized by the SILAR method. The obtained results clearly demonstrated a significant improvement in gas sensitivity by incorporating In into the ZnO.