Abstract
Spinel chromite nanoparticles are prospective candidates for a variety of applications from catalysis to depollution. In this work, we used a sol–gel auto-combustion method to synthesize spinel-type MgCr2O4 nanoparticles by using fructose (FS), tartaric acid (TA), and hexamethylenetetramine (HMTA) as chelating/fuel agents. The optimal temperature treatment for the formation of impurity-free MgCr2O4 nanostructures was found to range from 500 to 750 °C. Fourier transform infrared (FTIR) spectroscopy was used to determine the lattice vibrations of the corresponding chemical bonds from octahedral and tetrahedral positions, and the optical band gap was calculated from UV–VIS spectrophotometry. The stabilization of the spinel phase was proved by X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis. From field-emission scanning electron microscopy (FE-SEM), we found that the size of the constituent particles ranged from 10 to 40 nm. The catalytic activity of the as-prepared MgCr2O4 nanocrystals synthesized by using tartaric acid as a chelating/fuel agent was tested on the decomposition of hydrogen peroxide. In particular, we found that the nature of the chelating/fuel agent as well as the energy released during the auto-combustion played an important role on the structural, optical, and catalytic properties of MgCr2O4 nanoparticles obtained by this synthetic route.
Highlights
IntroductionSpinel-type oxides, with the general formula AB2 O4 (where A is divalent metal andB is trivalent metal), are some of the most technologically important materials, having played a key role in the development of modern electronics [1], in nuclear technology as a radiation-resistant materials [2], etc
Spinel-type oxides, with the general formula AB2 O4, are some of the most technologically important materials, having played a key role in the development of modern electronics [1], in nuclear technology as a radiation-resistant materials [2], etc
The electron microscopy data showed that the average size of the nanoparticles increased with increasing enthalpy value of combustion of the fuel agent
Summary
Spinel-type oxides, with the general formula AB2 O4 (where A is divalent metal andB is trivalent metal), are some of the most technologically important materials, having played a key role in the development of modern electronics [1], in nuclear technology as a radiation-resistant materials [2], etc. A valuable alternative is the sol–gel auto-combustion synthesis [16,17,18] as an easy and cheap method for forming high-quality nanoparticles According to this method, MgCr2 O4 nanoparticles are synthesized via a multi-step procedure including the dissolution of stoichiometric amounts of metal precursors and the chelating/fuel agent into an appropriate solvent, the formation of a gel, followed by the gradual increase of the reaction temperature and initiation of auto-combustion, during which the main chemical reactions occur, followed by the final calcination step. MgCr2 O4 nanoparticles are synthesized via a multi-step procedure including the dissolution of stoichiometric amounts of metal precursors and the chelating/fuel agent into an appropriate solvent, the formation of a gel, followed by the gradual increase of the reaction temperature and initiation of auto-combustion, during which the main chemical reactions occur, followed by the final calcination step This synthetic method for the fabrication of spinel nanostructures allows for the growth of the nanoparticles with predictable properties. A proper selection of the chelating/fuel agent, metal precursors, and reaction conditions are oftentimes crucial to the purity and morphological characteristics of the final product that, in turn, will strongly influence the electrical, catalytic, magnetic, and optical properties of these spinel nanoparticles
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