Sol-Gel-Prepared Ni-Mo-Mg-O System for Catalytic Transformation of Chlorinated Organic Wastes into Nanostructured Carbon

Veselov, Grigory B.; Karnaukhov, Timofey M.; Bauman, Yury I.; Mishakov, Ilya V.; Vedyagin, Aleksey A.

doi:10.3390/ma13194404

Cited by 13 publications

(7 citation statements)

References 41 publications

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“…In this case, the second component should be further introduced in the form of organometallic compounds [ 18 ], which are exotic and expensive precursors. An alternative approach has been reported in a number of recent publications [ 19 , 20 , 21 , 22 , 23 ]. In these papers, the hydrolysis stage was efficiently performed using an aqueous solution of the inorganic salt precursor.…”

Section: Introductionmentioning

confidence: 99%

Preparation of the Nanostructured Ni-Mg-O Oxide System by a Sol–Gel Technique at Varied pH

et al. 2022

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In the present work, a series of two-component Ni-Mg-O oxide systems were prepared using a sol–gel technique at varied pH of hydrolysis procedure. The aqueous solutions of nitric acid or ammonia were added to control the pH values. The xerogel samples obtained after drying were analysed using a thermogravimetric approach. The oxide systems were characterized by a set of physicochemical methods (low-temperature nitrogen adsorption, X-ray diffraction analysis, scanning electron microscopy, UV-vis spectroscopy, and temperature-programmed reduction method). The thermal stability of the samples was examined in a testing reaction of CO oxidation in a prompt thermal aging regime. It was revealed that the pH value during the magnesium methoxide hydrolysis stage significantly affects the properties of the intermediate hydroxide and final oxide nanomaterials. The thermal decomposition of nitric acid or ammonia is accompanied by exothermal effects, which noticeably influence the textural characteristics. Moreover, the pH of the hydrolysing solution defines the strength of the nickel interaction with the MgO matrix. An increase in pH facilitates the formation of the NixMg1−xO solid solution with a higher amount of incorporated nickel, which is characterized by the reproducible broad temperature range of the hydrogen uptake and the enhanced thermal stability.

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Section: Introductionmentioning

confidence: 99%

Preparation of the Nanostructured Ni-Mg-O Oxide System by a Sol–Gel Technique at Varied pH

et al. 2022

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“…In this case, DCE was fed into the reactor through the saturation route. This scheme was utilized in a number of recently published papers [9,11,[21][22][23]. The main disadvantages of this scheme should be noted.…”

Section: Resultsmentioning

confidence: 99%

“…Despite the high resistance of Ni to the chlorine action, pure nickel catalysts undergo deactivation caused by the formation of amorphous carbon blocking the active surface of nickel particles. Doping nickel with other metals (Cr, Co, Cu, Mo, W, Pd, Pt) results in the enhanced activity and elongated stability of Ni-based catalysts [11,21,22]. It should be emphasized that both bulk alloys and specially prepared porous alloy systems can serve as precursors of self-organizing catalysts [11,23].…”

Section: Introductionmentioning

confidence: 99%

Scaling up the Process of Catalytic Decomposition of Chlorinated Hydrocarbons with the Formation of Carbon Nanostructures

et al. 2022

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Catalytic processing of organochlorine wastes is considered an eco-friendly technology. Moreover, it allows us to obtain a value-added product—nanostructured carbon materials. However, the realization of this process is complicated by the aggressiveness of the reaction medium due to the presence of active chlorine species. The present research is focused on the characteristics of the carbon product obtained over the Ni-Pd catalyst containing 5 wt% of palladium in various quartz reactors: from a lab-scale reactor equipped with McBain balance to scaled-up reactors producing hundreds of grams. 1,2-dichloroethane was used as a model chlorine-substituted organic compound. The characterization of the materials was performed using scanning and transmission electron microscopies, Raman spectroscopy, and low-temperature nitrogen adsorption. Depending on the reactor type, the carbon yield varied from 14.0 to 24.2 g/g(cat). The resulting carbon nanofibers possess a segmented structure with disordered packaging of the graphene layers. It is shown that the carbon deposits are also different in density, structure, and morphology, depending on the type of reactor. Thus, the specific surface area changed from 405 to 262 and 286 m2/g for the products from reactor #1, #2, and #3, correspondingly. The main condition providing the growth of a fluffy carbon product is found to be its ability to grow in any direction. If the reactor walls limit the carbon growing process, the carbon product is represented by very dense fibers that can finally crack the reactor.

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“…The sol-gel techniques give a number of advantages, including the mentioned small particle size and uniform distribution of one component within the matrix of another component serving as the support. Recently, such a sol-gel approach was successfully applied to prepare the two- and three-component oxide systems based on the MgO matrix [ 57 , 58 , 59 , 60 ]. Magnesium oxide is a unique material possessing attractive textural characteristics such as developed specific surface area and porosity.…”

Section: Introductionmentioning

confidence: 99%

Sol-Gel Synthesis and Characterization of the Cu-Mg-O System for Chemical Looping Application

et al. 2022

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A sol-gel technique was applied to prepare the two-component oxide system Cu-Mg-O, where MgO plays the role of oxide matrix, and CuO is an active chemical looping component. The prepared samples were characterized by scanning electron microscopy, low-temperature nitrogen adsorption, and X-ray diffraction analysis. The reduction behavior of the Cu-Mg-O system was examined in nine consecutive reduction/oxidation cycles. The presence of the MgO matrix was shown to affect the ability of CuO towards reduction and re-oxidation significantly. During the first reduction/oxidation cycle, the main characteristics of the oxide system (particle size, crystallization degree, etc.) undergo noticeable changes. Starting from the third cycle, the system exhibits a stable operation, providing the uptake of similar hydrogen amounts within the same temperature range. Based on the obtained results, the two-component Cu-Mg-O system can be considered as a prospective chemical looping agent.

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Sol-Gel-Prepared Ni-Mo-Mg-O System for Catalytic Transformation of Chlorinated Organic Wastes into Nanostructured Carbon

Cited by 13 publications

References 41 publications

Preparation of the Nanostructured Ni-Mg-O Oxide System by a Sol–Gel Technique at Varied pH

Preparation of the Nanostructured Ni-Mg-O Oxide System by a Sol–Gel Technique at Varied pH

Scaling up the Process of Catalytic Decomposition of Chlorinated Hydrocarbons with the Formation of Carbon Nanostructures

Sol-Gel Synthesis and Characterization of the Cu-Mg-O System for Chemical Looping Application

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