Commercially available powders of detonation nanodiamond (DND) contain extrastrong 20-120 nm sized aggregates, in an amount sometimes up to 50% by mass sustainable to the conventional methods of deaggregation. It demonstrates the significant inhomogeneity structure of products of detonation synthesis and noticeably reduces the yield of 4.0 - 5.0 nm individual isolated particles obtained from DNDs. The presence of these aggregates is obviously related to the some essential features of detonation synthesis. This work presents the results of studying such extrastrong aggregates from DND powder. In order to determine the structure we applied the heat treatment of samples in vacuum and in air, and the subsequent study using Raman spectroscopy, X-ray diffraction, UV-vis spectroscopy, analysis of specific surface and dynamic light scattering (DLS). As a result, a structural model of extrastrong aggregates is proposed. It is shown that extrastrong aggregates consist notably of relatively large (similar to 8.0 nm) single crystalline diamond particles bonded by facets and covered by smaller 4.5 - 3.0 nm and less crystalline grains. Our results add the details for description of formation processes of diamond particles and aggregates in detonation synthesis from excessive carbon in the composition of explosives.

A new method of using the detonation nanodiamond with positive and negative zeta potential as a spacer for aerogels based on graphene oxide is presented. It is shown that the dosed addition of detonation nanodiamonds' particles to the suspension of graphene oxide hydrosol made it possible to triple the specific surface area of the resulting aerogel compared to graphene oxide aerogel, and this effect is more significant when nanodiamonds with a positive zeta potential are used. It was also shown that aerogels derived from graphene oxide and detonation nanodiamond with a positive zeta potential have a specific morphology with graphene oxide platelets being twisted. This effect is discussed in terms of the change in the average zeta potential of the initial mixtures. Keywords: two-component systems, carbon materials, colloid chemistry.

The properties of graphene oxide-detonation nanodiamond composites obtained as a result of heterocoagulation of graphene oxide and hydrogenated detonation nanodiamonds in aqueous mixtures were studied. The resulting composites with different proportions of graphene oxide and detonation nanodiamond were subjected to drying and subsequent heat treatment in a vacuum, converting graphene oxide into graphene. The structure of the composites was studied using electron microscopy and Raman spectroscopy. The specific surface area and porosity of the obtained samples were studied by analyzing nitrogen adsorption isotherms. A model for the composite formation and a possible technology for producing a material based on it with different specific surface area values and pore structure are proposed. It is shown, that the largest possible specific surface area of two-component structures of the << DND/GO >> type does not exceed 500 m2 center dot g-1. It was also concluded that it is necessary to achieve a uniform distribution of detonation nanodiamond particles over the surface of graphene sheets.

The paper is devoted to basic properties study of hydrogenated detonation nanodiamonds. It is shown that a powder of detonation nanodiamond annealed in molecular hydrogen contains carbonate and bicarbonate ions. These anions may be replaced for other anions during the interaction of the nanodiamond particles with aqueous solutions of salts and acids. The anion replacement is confirmed by Infrared and Energy dispersive X-ray spectroscopies. The presence of carbonate and bicarbonate ions indicates that the hydrogenated diamond nanoparticles have a positive surface charge in the powder according surface transport doping. Potentiometric titration and nitrogen adsorption methods have been used to calculate the surface charge of the particles.

Foam-like nanocomposites of the Ce-Fe-O system with two (c-CeO2, am-F2O3), three (c-CeO2, o-CeFeO3, a-F2O3), or four phases (c-CeO2, o-CeFeO3, a-F2O3, am-Fe2O3) were synthesized using the RedOx reaction of glycine-nitrate combustion. The glycine/nitrate ratio (G/N) varied from deficient (0.2, 0.4) and stoichiometric (0.6) to excess ratios of glycine (0.8, 1.0, 1.2, 1.4). PXRD, 57Fe Moeurossbauer spectroscopy, N2physisorption, TEM, H2-TPD, O2-TPD, and H2-TPR were used to examine the characteristics of the obtained samples. The average crystallite size of the obtained composites was in the range of 1.3-31.3 nm, 33.4-50.7 nm, and 10.1-33.9 nm for c-CeO2, o-CeFeO3, and a-Fe2O3, respectively. The lowest SBET (1.5 m2/g) belonged to the case of stoichiometric G/N, while the highest value (49.2 m2/g) was found in the case of the highest amount of glycine (G/N = 1.4); the latter case also had the largest total pore volume (Vp = 0.182 cm3/g) when compared to the others. Moreover, the advanced catalytic performance of foamy Ce-Fe-O-based nanocomposites toward H2 combustion in air was found with t10 = 275 & DEG;C, t50 = 345 & DEG;C, and Ea = 76.9 kJ/mol for sample G/N = 1.2. The higher activity of sample G/N = 1.2 in catalysis was attributed to different properties of the composite, including an appropriate component phase ratio, the smaller size of crystallites, higher specific surface area, higher reducibility,oxygen capacity, etc. The findings make it possible to carry out the directed synthesis of catalysts based on the Ce -Fe-O system with specific phases, dispersion, and morphological composition for efficient hydrogen oxidation at moderate temperatures.& COPY; 2023 Vietnam National University, Hanoi. Published by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The impact of the fuel/oxidizer ratio, the fuel type and the oxygen excess in the synthesis of ceria supported Ni and Co catalysts on the physicochemical properties and activity in steam and aqueous-phase reforming of glycerol was studied.

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

The new applications of nanodiamond in biology and nuclear physics require the use of products with a low content of impurities.One of the possible methods for obtaining a high-purity nanodiamond is the recently developed laser synthesis method.The aim of this work was to study the state of aggregation of laser synthesis nanodiamond particles in aqueous suspensions and to test the possibility of deaggregation of laser nanodiamond.The process of deaggregation of a laser synthesis nanodiamond is investigated.It was shown that the previously described process of deaggregation by milling with baking soda and the usual process of deaggregation give almost the same results.A solid phase from a colloidal solution of a laser synthesis nanodiamond has been isolated and investigated.The low content of impurities in the studied product was confirmed (less than 0.1% at.), the Raman, IR, and EPR spectra were studied.

Представлен новый способ использования детонационного наноалмаза с положительным и отрицательным знаком дзета-потенциала в качестве разделителя для аэрогелей на основе оксида графена. Показано, что дозированное добавление в суспензию оксида графена гидрозоля частиц детонационных наноалмазов позволило троекратно увеличить удельную поверхность образующегося аэрогеля по сравнению с аэрогелем оксида графена, и этот эффект значительнее при использовании наноалмазов с положительным дзета-потенциалом. Также показано, что полученные из оксида графена и детонационного наноалмаза с положительным дзета-потенциалом аэрогели обладают специфической морфологией: пластины оксида графена при этом скручены. Этот эффект обсуждается с точки зрения изменения среднего дзета-потенциала исходных смесей. Ключевые слова: двухкомпонентные системы, углеродные материалы, коллоидная химия.

In this paper, we propose a facile approach to the management of graphene oxide (GO) chemistry via its synthesis using KMnO4/K2Cr2O7 oxidizing agents at different ratios. Using Fourier Transformed Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, and X-ray Absorption Spectroscopy, we show that the number of basal-plane and edge-located oxygenic groups can be controllably tuned by altering the KMnO4/K2Cr2O7 ratio. The linear two-fold reduction in the number of the hydroxyls and epoxides with the simultaneous three-fold rise in the content of carbonyls and carboxyls is indicated upon the transition from KMnO4 to K2Cr2O7 as a predominant oxidizing agent. The effect of the oxidation mixture’s composition on the structure of the synthesized GOs is also comprehensively studied by means of X-ray diffraction, Raman spectroscopy, transmission electron microscopy, atomic-force microscopy, optical microscopy, and the laser diffraction method. The nanoscale corrugation of the GO platelets with the increase of the K2Cr2O7 content is signified, whereas the 10–100 μm lateral size, lamellar, and defect-free structure is demonstrated for all of the synthesized GOs regardless of the KMnO4/K2Cr2O7 ratio. The proposed method for the synthesis of GO with the desired chemistry opens up new horizons for the development of graphene-based materials with tunable functional properties.

One of the industrially scalable methods for the synthesis of diamond crystals is shock compression of graphite. The method includes shock compression of graphite with explosives (RDX). Typical sizes of polycrystalline diamond particles produced by the method are in the range from 50 nm to 2 mu m. We submit a method for deagglomeration of that diamond particles and production of stable hydrosol of monodisperse particles with positive electrokinetic potential. The mean size of isolated diamond particles in the hydrosol is 4 nm. The method includes chemical purification of the commercial diamond powder, annealing of purified powder in hydrogen, and followed centrifugation.

In this paper, we propose a facile approach to the management of graphene oxide (GO) chemistry via its synthesis using KMnO4/K2Cr2O7 oxidizing agents at different ratios. Using Fourier Transformed Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, and X-ray Absorption Spectroscopy, we show that the number of basal-plane and edge-located oxygenic groups can be controllably tuned by altering the KMnO4/K2Cr2O7 ratio. The linear two-fold reduction in the number of the hydroxyls and epoxides with the simultaneous three-fold rise in the content of carbonyls and carboxyls is indicated upon the transition from KMnO4 to K2Cr2O7 as a predominant oxidizing agent. The effect of the oxidation mixture's composition on the structure of the synthesized GOs is also comprehensively studied by means of X-ray diffraction, Raman spectroscopy, transmission electron microscopy, atomic-force microscopy, optical microscopy, and the laser diffraction method. The nanoscale corrugation of the GO platelets with the increase of the K2Cr2O7 content is signified, whereas the 10-100 μm lateral size, lamellar, and defect-free structure is demonstrated for all of the synthesized GOs regardless of the KMnO4/K2Cr2O7 ratio. The proposed method for the synthesis of GO with the desired chemistry opens up new horizons for the development of graphene-based materials with tunable functional properties.

A structural study of graphene oxide complexes with detonation nanodiamonds (particle size 4–5 nm, positive surface potential) in aqueous suspensions by small-angle neutron scattering is reported. While the pure graphene oxide suspension exhibits a completely planar structure, the grafting of detonation nanodiamond particles results in a slightly curved surface of the graphene oxide flakes. The complexes “graphene oxide–detonation nanodiamonds” washed out from free detonation nanodiamonds show that the effective curvature of the graphene oxide plane is the result of binding of detonation nanodiamonds in the form of planar aggregates.

Detonation nanodiamond is a commercially available synthetic diamond that is obtained from the carbon of explosives. It is known that the average particle size of detonation nanodiamond is 4–6 nm. However, it is possible to separate smaller particles. Here we suggest a new approach for the effective separation of detonation nanodiamond particles by centrifugation of a “hydrosol/glycerol” system. The method allows for the production of the detonation nanodiamond hydrosol with a very sharp distribution in size, where more than 85% of particles have a size ranging 1–4 nm. The result is supported by transmission electron microscopy, atomic force microscopy, and dynamic light scattering.

Monodisperse carbon nanodots and nanodiamond particles were studied by AFM method. Particle size distributions were calculated using AFM and DLS data. The results obtained correspond to TEM measurements. It was demonstrated that AFM allows detecting nanoparticles with sizes less than 2 nm. The average size of the particles for both samples was found to be ~4 nm. It was found that PSD for CND and DND was symmetric and asymmetric, correspondingly. Such difference can be understood in terms of different crystal structure perfection and the specific aspects of nanosized carbon preparation technology.