Advanced Size-Selected Catalysts Prepared by Laser Electrodispersion

Rostovshchikova, T. N.; Локтева, Е. С.; Голубина, Е. В.; Маслаков, К. И.; Gurevich, S. A.; Yavsin, D. A.; Kozhevin, V. M.

doi:10.1016/b978-0-12-814807-5.00003-6

Cited by 3 publications

(14 citation statements)

References 47 publications

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“…[22] It was well-established that the particle size in LED coatings is independent on the metal loading or surface density of particles. [9] Therefore, we can propose that the interaction with oxygen-containing surface groups is responsible for the fact that nickel oxidation is higher for isolated particles than for islands of particles in denser layers.…”

Section: Nipd Catalystsmentioning

confidence: 96%

“…Their deposition on the support surface makes it possible to produce "core-shell" size-selected catalysts in one stage without auxiliary chemical reagents, reduction agents and stabilizers, with these catalysts being unusually stable against aggregation and sintering. [9] The uniform distribution of finely dispersed amorphous nanoparticles only on the outer support surface provides high activity of LED catalysts at extremely low metal loadings (up to 10 À 3 wt.%). LED catalysts strongly differ in structure, adsorption and catalytic properties from supported catalysts synthesized by "wet" chemical methods.…”

Section: Introductionmentioning

confidence: 99%

“…The main advantage of this method is that the particle size of metal catalysts deposed by LED is independent of both the support type and the surface coverage degree. [9,13] The fast cooling of monodispersed nanodrops preliminarily produced in the laser plasma torch during their deposition on the support surface preserves their size, spherical shape and amorphous structure. Monometallic LED catalysts comprising Pd, Pt, Ni, Cu supported on carbon and oxide supports were widely studied in several classes of catalytic reactions, [9][10][11][12][13] and very promising results were achieved in environmentally important reactions of hydrodechlorination of chlorinated organic molecules.…”

Section: Introductionmentioning

confidence: 99%

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Bimetallic Nanostructured Catalysts Prepared by Laser Electrodispersion: Structure and Activity in Redox Reactions

et al. 2020

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One‐stage size‐selective method of laser electrodispersion (LED) was used to produce nanostructured NiPd, NiMo and NiW coatings on the surface of alumina, HOPG and Sibunit for the catalytic application. The deposition of nanoparticles produced by LED of bimetallic targets from alloyed or pressed metal powders provides the uniform distribution of both metals on the outer support surface; the metal ratio is similar to that in the original target. The catalytic behaviour of produced “core‐shell” catalysts in comparison with monometallic analogues was tested in two model reactions: the CO oxidation with oxygen on NiPd catalysts supported on alumina and Sibunit; and thiophene oxidation with hydrogen peroxide on NiMo and NiW alumina supported catalysts. Novel LED bimetallic catalysts with extremely low metal content (0.005 %) were superior in terms of activity and stability to monometallic ones and the catalysts obtained by “wet” chemistry methods. Improved catalytic properties of bimetallic LED catalysts are related to the high density of single nanoparticles and the formation of active metal‐oxide interfaces on the support surface.

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Section: Nipd Catalystsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bimetallic Nanostructured Catalysts Prepared by Laser Electrodispersion: Structure and Activity in Redox Reactions

et al. 2020

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“…В работе [8] полагалось, что такой характер каскадного деления сохраняется при всех размерах частиц, и в финальной стадии такого деления могут формироваться капли с размером вплоть до нанометров. В то же время из результатов более поздних оценок, представленных, например, в [11,12], следовало, что основной причиной остановки процесса деления является резкий рост интенсивности эмиссии электронов с поверхности капель, заряженных до предела Рэлея, который возникает при уменьшении их размеров этих капель до нескольких нанометров.…”

Section: Particle Numberunclassified

“…Такой метод, называемый методом лазерного электродиспергирования, был представлен в работах [11,12]. Основной особенностью этого метода является то, что зарядка и деление капель расплава происходят при погружении этих капель в плотную плазму лазерного факела, вследствие чего подзарядка этих капель происходит постоянно.…”

Section: Particle Numberunclassified

Влияние Термополевой Эмиссии Электронов На Формирование Аморфных Металлических Наночастиц В Плазме Лазерного Факела

Борматов¹,

Кожевин²,

Гуревич³

2021

Журнал Технической Физики

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В последние годы значительно усилился интерес к использованию структур, состоящих из аморфных наночастиц, который обусловлен их необычными электрическими, магнитными и каталитическими свойствами. Одной из важных задач, стоящих на пути к практическому применению таких структур, является разработка новых технологий их формирования. Исследования, проведенные в рамках решения этой задачи, показали, что наиболее эффективным способом получения аморфных металлических наночастиц является дробление микрокапель металлов, заряжаемых в плазме лазерного факела. Однако, несмотря на то, что использование этого метода позволило создать такие структуры из различных типов металлов, теоретический анализ эффекта дробления микрокапель проведен без детального рассмотрения процесса зарядки нанометровых капель, что в значительной мере ограничивает возможность использования имеющихся теоретических моделей для разработки новых технологий. Представлена модель, позволяющая более точно определить требования к параметрам плазмы лазерного факела, при которых реализуется эффективное дробление микрокапель металлов до нанометровых размеров. Ключевые слова: термополевая эмиссия, плазма лазерного факела, аморфные наноструктуры, предел Рэлея, каскадное электродиспергирование.

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Metal-support interactions in the design of heterogeneous catalysts for redox processes

Локтева

Голубина

2019

Pure and Applied Chemistry

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The effect of the metal-support interaction (MSI) has been discussed for several types of catalytic systems comprising metal nanoparticles (Ni, Pd, Au, Fe) on oxide and carbon supports, showing promising catalytic properties in hydrogenation of unsaturated C–C bonds, hydrodechlorination (HDC) of chlorinated organic molecules and CO total oxidation. The MSI of a different strength, from the redistribution of the electron density of nanoparticles (NPs) to the chemical interactions, is determined by the composition of the support and the active site, the method of active metal deposition, calcination temperature, particle size etc. The types of MSI considered in this review include: (1) the interaction of the active metal (Me) NPs with alumina and modified zirconia to form several oxidation states of Me in the composition of surface or bulk chemical compounds with a support; (2) the influence of oxide (alumina, silica) or carbon (highly oriented pyrolytic graphite, Sibunit) supports on the formation of active sites in the catalysts with ultra-low Me loading prepared by deposition of pre-formed metal NPs produced by laser electrodispersion (LED) or as colloidal dispersion; (3) the anchoring of Me NPs on the surface of carbon supports (nanodiamonds and carbon nanotubes) directly with a support surface, e.g. through surface defects, or through surface functional groups; (4) ‘reverse’ MSI in the Me@C composites, consisting of metal NPs, covered with the defected graphene layers or immersed into carbon matrix. It is demonstrated on the example of LED systems, that oxidation of metal under MSI is less significant in carbon-supported systems than in oxide-supported ones, but charge effects can play a noticeable role for both types of supports. Different ways of MSI tuning provide the possibilities to achieve the optimal Men+/Me0 ratio in the catalysts for HDC of mono- and polychlorinated organic molecules, including persistent organic pollutants. One of these ways is tuning the composition of functional groups on the surface of nanodiamonds and carbon nanotubes by additional treatments to achieve the desirable metal anchoring, the optimal metal NPs size and the improved catalytic properties. Unusual type of MSI is represented by the activation of thin graphene shell of Me@C composites by the presence of defects in the shell and a transition metal (Ni, Fe) in subsurface layer. This effect allows H2 activation that is a significant step in many industrially important reactions. The selectivity and activity of such systems can be intentionally changed by varying the nature of metal and reaction temperature. Significant attention has been given in the review to the novel catalytic systems described in the previous works of the authors.

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Advanced Size-Selected Catalysts Prepared by Laser Electrodispersion

Cited by 3 publications

References 47 publications

Bimetallic Nanostructured Catalysts Prepared by Laser Electrodispersion: Structure and Activity in Redox Reactions

Bimetallic Nanostructured Catalysts Prepared by Laser Electrodispersion: Structure and Activity in Redox Reactions

Влияние Термополевой Эмиссии Электронов На Формирование Аморфных Металлических Наночастиц В Плазме Лазерного Факела

Metal-support interactions in the design of heterogeneous catalysts for redox processes

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