Zinc germanium phosphide (ZnGeP2) is an important nonlinear crystal for mid-infrared conversion, but its performance is limited by residual absorption and intrinsic impurity phases. In this study, polycrystalline ZnGeP2 was synthesized by a modified two-temperature method, purified by inclined directional recrystallization for up to three cycles, and then grown into single crystals by the vertical Bridgman method. The resulting material was examined by shadow-projection imaging, transmission spectroscopy in the 650-2500 nm range, absorption measurements at 2.097 µm, laser-induced damage threshold (LIDT) testing, and powder X-ray diffraction. Repeated purification improved optical homogeneity and near-infrared transparency, while the absorption coefficient at 2.097 µm decreased from 0.45 to 0.30 cm-1 after three purification cycles. Semi-quantitative PXRD analysis showed progressive suppression of intrinsic impurity phosphides, with phase purity increasing from 86.31% after the first cycle to 95.995% after the second and reaching 100% after the third within the detection limit of the method. However, the LIDT decreased with increasing purification number, indicating a trade-off between lower optical losses and damage resistance. These results demonstrate that inclined directional recrystallization is an effective pre-growth purification route for ZnGeP2 and that the optimal number of purification cycles should be selected according to the intended application.

Changes in the surface resistance of polyethylene based composite films modified by multi-walled carbon nanotubes (MWCNTs) as a result of laser treatment are studied. Composites containing uniformly distributed nanotubes throughout their volume are prepared by mechanical melt mixing. The composite surfaces are treated by a 1064 nm fiber laser while varying the pulse duration within the 3-120 ns range and the source power within the 0.6-21 W range, so that the surface energy density during processing is 0.1-18.3 J/cm2. The influence of laser treatment parameters on the surface structure of composites is studied by scanning electron microscopy and Raman spectroscopy, and the surface resistance is determined using a four-electrode circuit. It is established that the surface resistance of the MWCNT-modified polymer composites can be either decreased by 30-50 times or increased by up to 140 times by tuning the laser treatment parameters.

Presently, there is no single, clear route for the near-term production of the huge volumes of CO2-free hydrogen necessary for the global transition to any type of hydrogen economy. All conventional routes to produce hydrogen from hydrocarbon fossil fuels (notably natural gas) involve the production-and hence the emission-of CO2, most notably in the steam methane reforming (SMR) process. Our recent studies have highlighted another route; namely, the critical role played by the microwave-initiated catalytic pyrolysis, decomposition or deconstruction of fossil hydrocarbon fuels to produce hydrogen with low to near-zero CO2 emissions together with high-value solid nanoscale carbonaceous materials. These innovations have been applied, firstly to wax, then methane, crude oil, diesel, then biomass and most recently Saudi Arabian light crude oil, as well as plastics waste. Microwave catalysis has therefore now emerged as a highly effective route for the rapid and effective production of hydrogen and high-value carbon nanomaterials co-products, in many cases accompanied by low to near-zero CO2 emissions. Underpinning all of these advances has been the important concept from solid state physics of the so-called Size-Induced-Metal-Insulator Transition (SIMIT) in mesoscale or mesoscopic particles of catalysts. The mesoscale refers to a range of physical scale in-between the micro- and the macro-scale of matter (Huang W, Li J and Edwards PP, 2018, Mesoscience: exploring the common principle at mesoscale, Natl. Sci. Rev. 5, 321-326 (doi:10.1093/nsr/nwx083)). We highlight here that the actual physical size of the mesoscopic catalyst particles, located close to the SIMIT, is the primary cause of their enhanced microwave absorption and rapid heating of particles to initiate the catalytic-and highly selective-breaking of carbon-hydrogen bonds in fossil hydrocarbons and plastics to produce clean hydrogen and nanoscale carbonaceous materials. Importantly, also, since the surrounding 'bath' of hydrocarbons is cooler than the microwave-heated catalytic particles themselves, the produced neutral hydrogen molecule can quickly diffuse from the active sites. This important feature of microwave heating thereby minimizes undesirable side reactions, a common feature of conventional thermal heating in heterogeneous catalysis. The low to near-zero CO2 production of hydrogen via microwave-initiated decomposition or cracking of abundant hydrocarbon fossil fuels may be an interim, viable alternative to the conventional, widely-used SMR, that a highly efficient process, but unfortunately associated with the emission of vast quantities of CO2. Microwave-initiated catalytic decomposition also opens up the intriguing possibility of using distributed methane in the current natural gas structure to produce hydrogen and high-value solid carbon at either central or distributed sites. That approach will lessen many of the safety and environmental concerns associated with transporting hydrogen using the existing natural gas infrastructure. When completely optimized, microwave-initiated catalytic decomposition of methane (and indeed all hydrocarbon sources) will produce no aerial carbon (CO2), and only solid carbon as a co-product. Furthermore, reaction conditions can surely be optimized to target the production of high-quality synthetic graphite as the major carbon-product; that material of considerable importance as the anode material for lithium-ion batteries. Even without aiming for such products derived from the solid carbon co-product, it is of course far easier to capture solid carbon rather than capturing gaseous CO2 at either the central or distributed sites. Through microwave-initiated catalytic pyrolysis, this decarbonization of fossil fuels can now become the potent source of sustainable hydrogen and high-value carbon nanomaterials.This article is part of the discussion meeting issue 'Microwave science in sustainability'.

Проведено исследование влияния лазерной обработки пленок композитов на основе полиэтилена, модифицированного многостенными углеродными нанотрубками (МУНТ) на изменение их поверхностного сопротивления. Композиты с равномерным распределением нанотрубок по объему были получены путем механического смешения в расплаве. Обработку поверхности композитов проводили с использованием волоконного лазера с рабочей длиной волны 1064 нм. В процессе обработки варьировали длительность импульсов в диапазоне 3 – 120 нс и мощность источника в диапазоне 0.6 – 21 Вт, так что поверхностная плотность энергии при обработке составляла 0.1 – 18.3 Дж/см2. Влияние параметров лазерной обработки на структуру поверхности композитов исследовали методами растровой электронной микроскопии и спектроскопии комбинационного рассеяния, поверхностное сопротивление определяли с использованием 4-х электродной схемы. Установлено, что для полимерных композитов, модифицированных МУНТ, возможно как уменьшение поверхностного сопротивления до 30 – 50 раз так и его увеличение до 140 раз в зависимости от параметров лазерной обработки.

Оксиды Ca3Co4O9 синтезированы методом Печини и твердотельным методом. Для компактирования использовались метод искрового плазменного спекания (SPS), холодное прессование с последующим взрывным сжатием (метод взрыва) и метод быстрого горячего прессования (RHP). Компактирование методом взрыва с добавлением связующего AlN привело к максимальной добротности при комнатной температуре ZT300K = 0.161. Добавление многослойных углеродных нанотрубок (CNTs) в оксиды, синтезированные методом Печини, ведет к ухудшению характеристик. Увеличение концентрации CNTs в Ca3Co4O9, синтезированных твердотельным методом и компактированных RHP методом, ведет к увеличению добротности ZT300K до 0.048 в Ca3Co4O9+3 wt%CNTs.

This study demonstrates that diffusion doping of ZGP single crystals with impurity atoms (Mg, Se, Sn, Pb) leads to a decrease in the specific conductivity of the samples. Consequently, this results in reduced absorption in the terahertz frequency range (150–1000 μm). It has been shown that doping ZGP samples with selenium (Se) and lead (Pb) atoms reduces absorption in the infrared region from 0.3–0.6 cm−1 to 0.06–0.09 cm−1. Doping with tin (Sn) leads to a decrease in absorption only in the wavelength region near 2.1 μm from 0.2 cm−1 to 0.05 cm−1. The proposed mechanism for the decrease in infrared absorption is a reduction in zinc vacancies due to doping with impurity atoms. This research lays the groundwork for a technology that produces ZGP crystals with minimal absorption within the 2–8 μm wavelength range, eliminating the need for fast electron beam irradiation technology. This advancement will facilitate the fabrication of ZGP crystals with arbitrary apertures.

Zinc germanium phosphide (ZGP) crystals have garnered significant attention for their nonlinear properties, making them good candidates for powerful mid-IR optical parametric oscillators and second-harmonic generators. A ZnGeP2 single crystal was treated by deep magnetorheological processing (MRP) until an Angstrom level of roughness. The studies presented in this article are devoted to the experimental evaluation of the influence of deep removal (up to 150 μm) from the surface of a ZnGeP2 single crystal by magnetorheological polishing on the parameters of optical breakdown. It was shown that the dependence of the ZnGeP2 laser-induced damage threshold on MRP depth is a smooth monotonically decreasing logarithmic function. The obtained logarithmic dependence indicates the thermal nature of optical breakdown and the dependence of the ZnGeP2 laser-induced damage threshold on the concentration of surface absorbing defects.

Carbon–silica composite materials (CSCMs) containing different amounts of silica and carbon components are obtained using two silica precursors (silica sol and silane) and multiwalled carbon nanotubes (MWNTs). At the initial stage of obtaining CSCMs by method 1, a fine MWNT powder is subjected to impregnation by moisture capacity with silica sol; in accordance with method 2, MWNTs are treated with tetraethoxysilane and then subjected to hydrolysis and polycondensation. The silica (SiO2) content in the composites is varied in a range of 3–60 wt

The data on electrical and photoelectric characteristics of Ga2O3/ZnGeP2 hetero-structures formed by RF magnetron sputtering Ga2O3 target with a purity of (99.99%) were obtained. The samples are sensitive to UV radiation with a wavelength of λ = 254 nm and are able to work offline as detectors of short-wave radiation. Structures with Ga2O3 film that was not annealed at 400 °C show weak sensitivity to long-wavelength radiation, including white light and near-IR (λ = 808 and 1064 nm). After annealing in an air environment (400 °C, 30 min), ZnGeP2 crystals in contact with Ga2O3 show n-type conductivity semiconductor properties, the sensitivity of Ga2O3/ZnGeP2 hetero-structures increases in the UV and IR ranges; the photovoltaic effect is preserved. Under λ = 254 nm illumination, the open-circuit voltage is fixed at positive potentials on the electrode to Ga2O3, the short-circuit current increases by three orders of magnitude, and the responsivity increases by an order of magnitude. The structures detect the photovoltaic effect in the near-IR range and are able to work offline (remotely) as detectors of long-wavelength radiation.

The paper presents the results on the development of an optical coating for a single-crystal ZnGeP2 substrate based on a selenide-oxide pair of materials (ZnSe/Al2O3). The obtained coating ensures the operation of OPO in the mid-IR range up to 5 μm wavelengths. The possibility of ZnSe sputtering by the IBS method is shown. The obtained optical coating has a high laser-induced damage threshold (LIDT) value at a 2097 µm wavelength: WoE=3.51 J/cm2 in energy density and WoP= 101 W/cm2 in power density at a 10 KHz pulse repetition frequency and a pulse duration of 35 ns. Thus, it is shown for the first time that the pair of materials ZnSe/Al2O3 can be used for the deposition of optical coatings by the IBS method with high LIDT values for ZnGeP2 optical elements operating in the mid-IR range.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

Amorphous carbon (AC) is present in the bulk and on the surface of nanostructured carbon materials (NCMs) and exerts a significant effect on the physical, chemical and mechanical properties of NCMs. Thus, the determination of AC in NCMs is extremely important for controlling the properties of a wide range of materials. In this work, a comparative study of the effect of heat treatment on the structure and content of amorphous carbon in deposited AC film, nanodiamonds, carbon black and multiwalled carbon nanotube samples was carried out by TEM, XPS, XRD and Raman spectroscopy. It has been established that the use of the 7-peak model for fitting the Raman spectra makes it possible not only to isolate the contribution of the modes of amorphous carbon but also to improve the accuracy of fitting the fundamental G and D2 (D) modes and obtain a satisfactory convergence between XPS and Raman spectroscopy. The use of this model for fitting the Raman spectra of deposited AC film, ND, CB and MWCNT films demonstrated its validity and effectiveness for investigating the amorphous carbon in various carbon systems and its applicability in comparative studies of other NCMs.

Composite carbon–silica materials (CCSM), differing in the content of carbon and silica components, were obtained using two silicon dioxide precursors (silica sol and silane) and multi-walled carbon nanotubes (MWNTs). At the initial stage of obtaining CCSM by method 1, impregnation of finely dispersed MWCNT powder with silica sol was used, method 2 was carried out using treatment of MWCNTs with tetraethoxysilane followed by hydrolysis and polycondensation. The content of silica (SiO2) in the composites varied from 3 to 60 wt %. After drying and appropriate heat treatment at 250–350°C, the composite materials were studied by various physicochemical methods: nitrogen porosimetry, electron microscopy, X-ray fluorescence analysis, and synchronous thermal analysis. Significant differences in parameters were found depending on the chemical composition of CСSM, including textural characteristics. Thus, with an increase in the SiO2 content, the specific surface area of composite materials increased (by a factor of 2), and maxima were observed on the distribution curves over pore diameters (at 20–40 nm).The composite carbon–silica materials were tested as adsorbent for the preparation of heterogeneous biocatalysts (BC) for the low-temperature synthesis of esters; the active component of these BC was lipase immobilized exclusively on the carbon surface of nanotubes. With a decrease in the content of MWCNTs in the composite materials, the enzymatic activity and operational stability of biocatalysts, measured in the reaction of esterification of heptanoic acid (C7) with butanol (C4), decreased monotonically, reaching a 2–8-fold drop in activity at the maximum content of SiO2 (58 wt %).

K2CO3-containing sorbents supported on carbon nanotubes (CNT) were prepared via one-pot extrusion molding and heat treatment. The porous CNTs were mixed with a water-isopropyl alcohol solution of potassium acetate (CH3COOK) and extruded by a plunger extruder. After drying in air, extrudates were calcined at 500 degrees C in argon to obtain the sorbents with a K2CO3 weight content in a range of 13.1-44.8 wt %. Samples were characterized using various techniques (scanning electron microscopy (SEM), X-ray diffraction (XRD), and low-temperature nitrogen adsorption) and were tested in the process of carbon dioxide capture from ambient air. The sorbent with 44.8 wt % K2CO3 demonstrated the promising dynamic CO2-sorption capacity (up to 8.9 wt %) under temperature-swing adsorption (TSA) cycle conditions. Taking into account that the sorbents need a relatively low temperature for regeneration (150 degrees C) while demonstrating high CO2-sorption capacity in the sequence of TSA cycles, these sorbents may be of interest for direct air capture applications.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

In this work, we studied the possibility of using composites based on multi-walled carbon nanotubes (MWCNTs) decorated with silicon (Si) and silicon carbide (SiC) particles as an anode material in lithium-ion current sources. MWCNTSi and MWCNT-SiC composites (with different Si/SiC ratios) were obtained by high-temperature heat treatment of MWCNT-Si at different temperatures (1040 and 1350 °C). The structure and phase composition of the composites were characterized by TEM and XRD methods. The determination of the specific capacity of composites as an anode material was carried out at current densities from 0,05 to 2 A/g.

Ex situ methods (TEM, XRD, and Raman spectroscopy) have been used to study the processes occurring at the multi-walled carbon nanotube/silicon interfaces (MWCNT/Si) during heat treatment of MWCNT-Si composites containing highly dispersed Si particles deposited on the surface of MWCNTs by CVD method. It has been established that during heat treatment, starting from 900 degrees C, the formation of SiC particles occurs. A further increase in temperature leads to the formation of polycrystalline SiC particles and a significant shortening of MWCNTs due to the reaction between Si particles and the surface of MWCNTs. It is shown that one can control the size of the formed SiC crystallites by varying the time and temperature of heat treatment. The kinetic dependences of the SiC formation process were studied within the Avrami-Erofeev model. The activation energy for the formation of SiC is estimated at 470 kJ/mol. The influence of heat treatment on the electrical conductivity and porosity of MWCNT-Si composites in the pressure range of 25-175 MPa has been studied.

A multilayer antireflection coating based on titanium oxide and silicon oxide has been developed. The dispersions of the refractive index and absorption coefficient of these materials are obtained in a wide spectral region of 500-8000 nm. Taking into account these dispersions, a calculation was made of a four-layer interference coating with ZGP substrate antireflection in the range of 2097 nm and 3500-5000 nm, with residual reflection R≤0.2% and R≤2.1%, respectively. The modes of coating deposition by the method of ion-beam sputtering on the substrate are selected.

The increasing resistance of bacteria and fungi to antibiotics is one of the health threats facing humanity. Of great importance is the development of new antibacterial agents or alternative approaches to reduce bacterial resistance to available antibacterial drugs. Due to the complexity of their properties, carbon nanomaterials (CNMs) may be of interest for a number of biomedical applications. One of the problems in studying the action of CNMs on microorganisms is the lack of universally standardized methods and criteria for assessing antibacterial and antifungal activity. In this work, using a unified methodology, a comparative study of the antimicrobial properties of the CNM systemic kit against common opportunistic microorganisms, namely Escherichia coli and Staphylococcus aureus, was carried out. Multiwalled carbon nanotubes (MWNTs), catalytic filamentous carbon with different orientations of graphene blocks (coaxial–conical and stacked, CFC), ionic carbon (OLC), and ultrafine explosive nanodiamonds (NDs) were used as a system set of CNMs. The highest antimicrobial activity was shown by NDs, both types of CFCs, and carboxylated hydrophilic MWCNTs. The SEM results point out the difference between the mechanisms of action of UDD and CFC nanotubes.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и