Chemical Design of Carbon-Coated Al2o3 Nanoparticles

The novel approach to chemical design of carbon-coated Al2O3 nanoparticles with an average particle size of 8-10 nm was developed. Carbon coating was synthesised by modification of fumed alumina support with 4,4’-methylenebis-(phenylisocyanate) and its subsequent pyrolysis at 700oC. In order to synthesise the samples with increased carbon content, the grafting-pyrolysis cycle was repeated. The above mentioned synthetic route resulted in the samples with carbon loading of 7.6 and 14.5 wt. %. Characterisation of the synthesised samples with Raman, FTIR, TG/DTG-DTA, N2 adsorption and SEM techniques revealed the formation of continuous carbon coating on the surface of Al2O3 nanoparticles after the first grafting-pyrolysis cycle. The increase of the carbon loading on the alumina surface to 14.5 wt. % (two grafting-pyrolysis cycles) resulted in the formation of the carbon coating with more regular graphitic structure.Розроблений новий метод хімічного дизайну вуглецевого покриття на поверхні наночастинок пірогенного Al2O3 розміром 8–10 нм. Вуглецеве покриття синтезували шляхом модифікування поверхні пірогенного оксиду алюмінію 4,4-метилендифенілдиізоціанатом та подальшим його піролізом при 700oC. З метою одержання зразків з більш високим вмістом вуглецю цикл "модифікування–піроліз" повторювали. Вищеописана процедура дозволила синтезувати зразки з вмістом вуглецю 7,6 та 14,5 % ваг. Дослідження синтезованих зразків методами раманівської та ІЧ-спектроскопії, TГ/ДTГ-ДTA, низькотемпературної адсорбції азоту та СЕM показало, що утворення суцільного вуглецевого покриття на поверхні пірогенного Al2O3 відбувається вже після проведення першого циклу "модифікування–піроліз". Повторення циклу "модифікування–піроліз" МДІ приводить до формування вуглецевого покриття з більш впорядкованою графітовою структурою.Разработан новый метод химического дизайна углеродного покрытия на поверхности наночастиц пирогенного Al2O3 размером 8–10 нм. Углеродное покрытие было синтезировано путем модифицирования поверхности пирогенного оксида алюминия 4,4–метилендифенилдиизоцианатом с последующим его пиролизом при 700oC. Для того чтобы синтезировать образцы с более высоким содержанием углерода, цикл "модифицирование–пиролиз" повторяли. Описанная выше процедура позволила синтезировать образцы с содержанием углерода 7,6 и 14,5% вес. Исследование синтезированных образцов методами рамановской и ИК-спектроскопии, TГ/ДTГ-ДTA, низкотемпературной адсорбции азота и СЭM показало, что образование сплошного углеродного покрытия на поверхности пирогенного Al2O3 происходит уже после проведения первого цикла "модифицирование–пиролиз". Повторение цикла "модифицирование–пиролиз" МДИ приводит к формированию углеродного покрытия с более упорядоченной графитовой структурой

Magnetometric Studies of Catalyst Refuses in Nanocarbon Materials

It is shown that magnetometry can be employed as an effective tool to control the content of a ferromagnetic constituent in nanocarbon materials. We propose a thermochemical treatment protocol to achieve extensive cleaning of the source nanocarbon materials from ferromagnetic refuses

Index of the consumer society development: Theoretical basis and primary validation

The article considers a range of issues in the analysis of the consumer society in order to develop an index that characterizes states in terms of the degree of their ‘consumerization’. The authors suggest the staging of social changes in the development of the consumer society, the possibility of comparing societies on a scale that reflects this staging, and the presence of distinctive features determined by the mechanism of transition to this type of society. The article explains the role of individual demand, the quantitative increase in the possibilities of which is reflected in its qualitative structure, which determines the growth of the non-material demand, the potential of which far exceeds any possible demand for material goods. Based on the review of studies and statistical data, the authors confirm the central role of branding in the consumer society and develop the consumerization index (IC) as a natural logarithm of the product of the average per capita number of registered trademarks (T) and average per capita consumer spending (S) of households (IC=ln(S×T)). The index reflects the space of consumption opportunities for the average individual in a particular society. According to the authors’ calculations, the lowest values of the index are observed in the poor countries of Asia and Africa, where the consumer society is obviously undeveloped, while the maximum values of the index — in the regions that can be considered a reference in terms of consumption. The authors assessed the convergent and discriminant validity of the index on the indicators of the information society development, economic, political and cultural globalization, and the connections it generates correspond to theoretical expectations. Thus, the constructed index can be considered a valid indicator and can be used in empirical cross-country comparisons based on the concept of the consumer society. © N.S. Babich, I.V. Batykov, 2022

Effect of V in La2NixV1−xO4+δ on selective oxidative dehydrogenation of propane

In this study, non-stoichiometric redox compounds such as La2NiO4+δ, La2Ni0.95V0.05O4.07+δ and La2Ni0.9V0.1O4.15+δ have been tested as oxidants in selective oxidation of propane, in order to judge the suitability of these materials for a dense membrane reactor for selective propane oxidation. Reducibility of the samples has been investigated using temperature programmed reduction in H2/Ar flow. The catalysts’ activity and selectivity at 550 °C have been investigated employing sequential pulses of diluted propane over the oxides.\ud \ud Pulsing with propane induces step-by-step reduction of the oxide; consequently, the activity of remaining oxygen decreases with the number of pulses, affecting the products distribution. It is observed that at 550 °C on oxidized catalysts CO2 and H2O are the main products and the selectivity towards propylene is very low. At a certain reduction level, obtained after pulse 8 in our experiments, the production of CO2 stopped without changing the amount of C3H6 produced. At this stage, also CH4 and C2H4 are being formed. V-doped catalysts have shown a constant level of C3H6 production within a broad window of oxidation degree, while the performance of La2NiO4+δ, catalyst deteriorated drastically after just a few pulses. CO, CH4 and coke deposits are formed with La2NiO4+δ, caused by the formation of metallic Ni. Vanadium is able to prevent this phenomenon, thus drastically broadening the window of selective oxidation of propane

Nature of nitrogen specie in coke and their role in NOx formation during FCC catalyst regeneration.

NOx emission during the regeneration of coked fluid catalytic cracking (FCC) catalysts is an environmental problem. In order to follow the route to NOx formation and try to find ways to suppress it, a coked industrial FCC catalyst has been prepared using model N-containing compounds, e.g., pyridine, pyrrole, aniline and hexadecane¿pyridine mixture. Nitrogen present in the FCC feed is incorporated as polyaromatic compounds in the coke deposited on the catalyst during cracking. Its functionality has been characterized using XPS. Nitrogen specie of different types, namely, pyridine, pyrrolic or quaternary-nitrogen (Q-N) have been discriminated. Decomposition of the coke during the catalyst regeneration (temperature programmed oxidation (TPO) and isothermal oxidation) has been monitored by GC and MS measurements of the gaseous products formed. The pyrrolic- and pyridinic-type N specie, present more in the outer coke layers, are oxidized under conditions when still large amount of C or CO is available from coke to reduced NOx formed to N2. ¿Q-N¿ type species are present in the inner layer, strongly adsorbed on the acid sites on the catalyst. They are combusted last during regeneration. As most of the coke is already combusted at this point, lack of reductants (C, CO, etc.) results in the presence of NOx in the tail gas