Measuring the thickness of ALD-fabricated thin films by small-angle X-ray scattering

The described research examined the adsorption of fluoride ions from solution immobilized onto an aluminum oxide-coated bacterial cellulose-based composite material in which aluminum oxide had been deposited using ALD technology. The kinetic regularities of the adsorption of fluoride ions from the solution as well as the mechanism of the processes were analyzed. The established equations show that the dynamics of adsorption correspond to first-order kinetics. Based on the Langmuir adsorption isotherms, we defined the adsorption equilibrium constants, parameter maximum adsorption, and change in Gibbs free energy. It is shown that, with increasing temperature, an increase in the reaction rate is constant, both forward and reverse. This testifies to the activated character of adsorption of the first fluoride on the surface of the sorbent based on bacterial cellulose modified with an alumina nanolayer. The activation energy of the desorption process is higher than the activation energy of the adsorption process, which characterizes the adsorption as ionic. The negative value of entropy indicates that in the course of sorption, an adsorption complex “aluminum-fluorine” is formed, where the system is more ordered than the initial system in which fluorine ions are in solution. The limiting stages of the process are revealed. The high sorption capacity of the resulting bacterial cellulose-based composite material obtained by means of biosynthesis through cultivation of the bacterium Komagataeibacter sucrofermentans B-11267 was demonstrated.

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“…Given that the equilibrium constant K c is defined as the ratio k 1 / k 2 , it is also possible to estimate the constants k 1 and k 2 [ 33 ].…”

Section: Resultsmentioning

confidence: 99%

Kinetic and Thermodynamic Characteristics of Fluoride Ions Adsorption from Solution onto the Aluminum Oxide Nanolayer of a Bacterial Cellulose-Based Composite Material

et al. 2021

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On the interplay between a novel iron and iron-carbide atomic layer deposition process, the carbon nanotube growth, and the metal–carbon nanotube coating properties on silica substrates

Cunha

Adjeroud

Guillot

et al. 2022

Journal of Vacuum Science &Amp; Technology A

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The fabrication of iron and iron carbide nanoparticles (NPs) for catalytic reactions such as the growth of carbon nanotubes (CNTs) compete with the challenge of covering a wide range of substrates with perfect control of the NP reactivity. We present in this work a novel atomic layer deposition (ALD) process to grow Fe/Fe3C thin films over silica flat substrates. The depositions were carried out exposing the surface through various number of ALD cycles, resulting in Fe-based films with thicknesses ranging from 4 nm to almost 40 nm. After a thermal treatment, the film dewetts into nanoparticles, where the efficiency to grow CNTs will depend on the average size distribution of the nanocatalyst. X-ray diffraction and x-ray photoelectron spectroscopy were used to track the elemental, phase, and shape (film to particles) transformation in order to identify the key features of the nanocatalyst, thereby controlling the CNT nucleation and growth. Thin film thickness of around 5 nm promotes the growth of a dense CNT forest. Furthermore, the metal–CNT films reveal optical properties that are totally tailored by the initial number of ALD cycles.

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Sorption of Fluoride Ions onto Cellulose and Aluminum Oxide Composites

Dolganov

Balandina

Chugunov

et al. 2020

Russ. J. Inorg. Chem.

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Measuring the thickness of ALD-fabricated thin films by small-angle X-ray scattering

Cited by 4 publications

References 2 publications

Kinetic and Thermodynamic Characteristics of Fluoride Ions Adsorption from Solution onto the Aluminum Oxide Nanolayer of a Bacterial Cellulose-Based Composite Material

Kinetic and Thermodynamic Characteristics of Fluoride Ions Adsorption from Solution onto the Aluminum Oxide Nanolayer of a Bacterial Cellulose-Based Composite Material

On the interplay between a novel iron and iron-carbide atomic layer deposition process, the carbon nanotube growth, and the metal–carbon nanotube coating properties on silica substrates

Sorption of Fluoride Ions onto Cellulose and Aluminum Oxide Composites

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