Centimetric-Sized Chromium (III) Oxide Object Synthesized by Means of the Carbon Template Replication

Pierre Gibot

doi:10.3390/ceramics3010010

Abstract

A simple, efficient synthesis approach for designing large ceramic pieces, herein termed chromium (III) oxide (Cr2O3) material, is provided. The process can be called the replica technique, or replication. The elaboration of a material with a unique morphology is a result of a ceramic salt coating that has been previously dissolved in ethylene glycol as the solvent; this process is performed on a carbon material surface that is selected as a template. Here, the carbon template was carbon fiber. After a heat treatment to convert the ceramic precursor to the corresponding ceramic oxide followed by the removal of the template, hollow ceramic oxide wires were obtained. The resulting material was characterized by X-ray diffraction, Raman and Fourier transform infrared spectroscopies, and scanning electron microscopy. The material exhibited a multiscale architecture, assembling nanosized nodules to form micron-sized tubes that assemble themselves into a centimetric structure. Objects with such tailored architectures can be used in a large variety of applications in fields as diverse as pyrotechnics, adsorption, and catalysis.

Highlights

Research in designing inorganic materials with well-defined and controlled multi-scale architectures is ubiquitous in the literature [1]
Chromium (III) oxide exhibits many unique properties, making it a candidate for several domains of application such as protective material in front of thermal and abrasive phenomena [3,4]; heterogeneous catalysis, for dehydrogenating alkanes such as propane ((CH3 )2 CH2 ) [5]; sensors for different species, like alcohol, ketone (acetone, (CH3 )2 CO), alkane (toluene, C6 H5 (CH3 )), and toxic gases like ammonia (NH3 ) and dichloride (Cl2 ) [6,7,8]; and pyrotechnic applications with the creation of energetic composites—where, when mixed with fuel-like aluminum (Al), they react according to a redox reaction and release a large amount of heat (10.9 kJ/cm3 ) that is tied to a high adiabatic temperature (2054 ◦ C) [9]
The carbon fibers were cleaned of any organic substances by heating them at 900 (15 h) under an argon flow (100 mL/min)

Summary

Introduction

Research in designing inorganic materials with well-defined and controlled multi-scale architectures is ubiquitous in the literature [1] These shapings largely contribute to improving the existing physicochemical properties of materials, but, sometimes, they reveal unexpected properties of raw materials [2]. Chromium (III) oxide’s global technic capabilities can be enhanced by nanostructuring the matter, allowing for the development of materials with large specific surface areas where the reactive area number is considerably improved, synonymous with optimized performance. To satisfy this permanent requirement of nanostructuring and/or developing complex architectured materials, in particular for the Cr2 O3 chromium (III) oxide, many processes

Methods

Results

Conclusion