Тип публикации: статья из журнала
Год издания: 2024
Идентификатор DOI: 10.1134/S1061933X23601075
Ключевые слова: synthetic valleriites, gold nanoparticles, x-ray photoelectron spectroscopy, transmission electron microscopy, zeta potential
Аннотация: Layered two-dimensional materials, whose properties dramatically differ from their bulk precursors, are of great theoretical and applied importance. Recently, a layered 2D material, an analog of a natural mineral, valleriite, in which quasi-monoatomic Cu−Fe−S sheets alternate with brucite-like ones, has been prepared using a simple hydrothermal synthesis procedure. The features of the electronic structure of these materials make it possible to propose them as new materials for a wide field of applications such as (electro)photocatalysis, high-capacity batteries, etc. In this work, nanocomposite materials have been prepared via immobilization of gold nanoparticles (AuNPs) from citrate hydrosols on the surface of the synthesized valleriites having different compositions of hydroxide layers, which control the surface charge density. According to X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive X-ray microanalysis (EDX), and selected area electron diffraction (SAED) data, AuNPs are immobilized on valleriite nanoflakes, which have lateral sizes of 150–200 nm and thicknesses of several tens of nanometers, as isolated metal nanoparticles with an average diameter of 11 nm. A small amount of aggregates indicates a high affinity of AuNPs for the valleriite surface. The amounts of immobilized gold are the same on all studied valleriites (~0.2%). This finding may be related to the simultaneous sorption of free citrate ions from the AuNP hydrosols, with these ions, according to zeta potential measurements, charging the surfaces of all studied valleriite samples to nearly the same negative value of –40 mV. According to the XPS data, the AuNPs immobilization markedly decreases the magnesium and oxygen contents on the surfaces of the synthesized valleriites due to the partial degradation/dissolution of the brucite layer. In addition, the amount of Fe3+ ions bound to OH groups decreases with a simultaneous increase in the fraction of Fe3+–O species. The TEM data have confirmed the preservation of the layered structure of valleriites after the immobilization of AuNPs.
Журнал: Colloid Journal
Выпуск журнала: Т.86, №1
Номера страниц: 40-51
ISSN журнала: 1061933X
Место издания: Москва
Издатель: Pleiades Publishing, Ltd. (Плеадес Паблишинг, Лтд)