Quantum Size Effect in Bimetallic Nanoparticles Obtained via Thermolysis of Solid Solutions of Co(II), Ni(II), Zn(II) Sa
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ICAL CHEMISTRY OF NANOCLUSTERS AND NANOMATERIALS
Quantum Size Effect in Bimetallic Nanoparticles Obtained via Thermolysis of Solid Solutions of Co(II), Ni(II), Zn(II) Salts of Maleic Acid L. I. Yudanovaа,*, V. A. Logvinenkoа,b, A. V. Ishchenkob,c, and N. A. Rudinab а Nikolaev
Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia b Novosibirsk State University, Novosibirsk, 630090 Russia c Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia *е-mail: [email protected] Received November 8, 2019; revised March 5, 2020; accepted March 17, 2020
Abstract—Powder X-ray diffraction and the thermoanalytical characteristics of solid solutions with compositions [(CoxNi1 – x)(H2O)4(C4H3O4)2], [(CoxZn1 – x)(H2O)4(C4H3O4)2], [(NixZn1 – x)(H2O)4(C4H3O4)2] (0 < x < 1) are compared. The decomposition of solid solutions and their constituents when heated to 500°C in a flow of He is conventionally divided into three stages. Products of the thermolysis of solid solutions are found to be Co/Ni, Co/ZnO, and Ni/Zn bimetallic nanoparticles, respectively, embedded into the polymeric matrix of composites. It is shown that the thermal decomposition of solid solutions in the Curie curve upon a second order phase transition with the formation of the two-phase region found in Co/Ni bimetallic nanoparticles is a quantum size effect. The decomposition of [(Co0.1Zn0.9)(H2O)4(С4H3O4)2] solid solution removes the Co atoms (d = 2.5 Å) embedded in channels of the ZnO structure. These atoms also serve as catalysts for the growth of a nanobrush of carbon nanotubes (CNTs) on the composite’s surface at ≤500°C, another consequence of the quantum size effect. It is concluded that using a similar catalyst of CNT growth can appreciably lower the energy of the process. Keywords: quantum size effect, thermal decomposition, solid solutions, maleates, nanoparticles, transition metals, nanotubes, metal/polymer composites, catalysts DOI: 10.1134/S0036024420100325
INTRODUCTION The development of new construction materials containing metallic and bimetallic nanoparticles (NPs) that can be used in particular for effective protection from electromagnetic radiation for biological objects, in catalysis, and in fabricating metal-containing solid fuel, requires new ways of preparing both individual particles and composites with metallic NPs [1–5]. An effective way of obtaining NPs is the thermal decomposition of salts of unsaturated carboxylic (acrylic, maleic) and aromatic (o-phthalic and terephthalic) acids of Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) transition metals. An example of this is thermal decomposition in a f low of He upon heating salts of maleic [M(H2O)n(С4H2O4)](H2O)m (n = 1, 2; m = 0, 1), [M(H2O)4(С4H3O4)2] (M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II)) and o-phthalic [M(H2O)n(С8H4O4)](H2O)m (n = 1, 2; m = 0–2); [M(H2O)6(С8H5O4)2] (M = Fe(II), Co(II), Ni(II)), [Cu(H2O)2(С8H5O4)2] acids [1, 4, 6, 7] to 500°C.
The average size of metal NPs obtained v
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