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Green and Unconventional Routes for the Synthesis of Crystalline Inorganic Materials —Selected Papers from AIM 2018

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (31 July 2019) | Viewed by 4588

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Guest Editor
Karlsruhe Institute of Technology, Engesserstr. 20, 76131 Karlsruhe, Germany
Interests: in situ studies of crystallisation phenomena; colloidal syntheses; functional nanomaterials

Special Issue Information

Dear colleagues,

The huge variety of experimental methodologies for the preparation of inorganic crystalline (nano)materials demonstrates the charms of preparative wet and colloidal chemistry and shows the great power of imagination. Each synthetic approach could, in turn, be optimized to yield shape controlled and nanostructured materials.

This Special Issue aims to collect examples of green and/or unconventional methods for the preparation of advanced inorganic materials, with special attention to those approaches with low environmental impact and complying with the twelve principles of Green chemistry.

The focuses of this Special Issue include, without being limited to, the following themes: flow or high-throughput methods, biogenic, template, microwave-assisted and solvothermal approaches, syntheses based on deep eutectic/supercritical/ionic liquid solvents, computational-assisted development of syntheses, and design-of-experiment.

Prof. Silvia Gross
Dr. Lucia Curri
Dr. Paolo Dolcet
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Colloids
  • Wet chemistry
  • New unconventional syntheses Green chemistry

Published Papers (1 paper)

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Research

16 pages, 4953 KiB  
Article
Nanocrystalline Transition-Metal Gallium Oxide Spinels from Acetylacetonate Precursors via Solvothermal Synthesis
by Daniel S. Cook, Reza J. Kashtiban, Klaus Krambrock, Geraldo M. de Lima, Humberto O. Stumpf, Luciano R. S. Lara, José D. Ardisson and Richard I. Walton
Materials 2019, 12(5), 838; https://doi.org/10.3390/ma12050838 - 12 Mar 2019
Cited by 4 | Viewed by 3996
Abstract
The synthesis of mixed-metal spinels based on substituted γ-Ga2O3 is reported using metal acetylacetonate precursors in solvothermal reactions with alcohols as solvents at 240 °C. New oxides of Cr, Mn and Fe have been produced, all of which are formed [...] Read more.
The synthesis of mixed-metal spinels based on substituted γ-Ga2O3 is reported using metal acetylacetonate precursors in solvothermal reactions with alcohols as solvents at 240 °C. New oxides of Cr, Mn and Fe have been produced, all of which are formed as nanocrystalline powders, as seen by high-resolution transmission electron microscopy (HR-TEM). The first chromium-gallium mixed oxide is thus formed, with composition 0.33Ga1.87Cr0.8O4 ( = vacant site). X-ray absorption near-edge spectroscopy (XANES) at the chromium K-edge shows the presence of solely octahedral Cr3+, which in turn implies a mixture of tetrahedral and octahedral Ga3+, and the material is stable on annealing to at least 850 °C. An analogous manganese material with average chemical composition close to MnGa2O4 is shown to contain octahedral Mn2+, along with some Mn3+, but a different inversion factor to materials reported by conventional solid-state synthesis in the literature, which are known to have a significant proportion of tetrahedral Mn2+. In the case of iron, higher amounts of the transition metal can be included to give an Fe:Ga ratio of 1:1. Elemental mapping using energy dispersive X-ray spectroscopy on the TEM, however, reveals inhomogeneity in the distribution of the two metals. This is consistent with variable temperature 57Fe Mössbauer spectroscopy that shows the presence of Fe2+ and Fe3+ in more than one phase in the sample. Variable temperature magnetisation and electron paramagnetic resonance (EPR) indicate the presence of superparamagnetism at room temperature in the iron-gallium oxides. Full article
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