Microwave‐Hydrothermal Synthesis of Nanostructured Zinc‐Copper Gallates

Abstract

Zinc gallate is an important semiconductor for manifold applications, e.g. in field emission displays or as a photocatalyst for water splitting. In addition to these interesting properties, zinc gallate is also an excellent matrix material that can be furthermore tuned through the incorporation of guest cations to form functional solid solutions with new optical and catalytic properties. We present a convenient microwave‐hydrothermal synthesis of nanostructured Cu2+‐substituted ZnGa2O4 spinels and their characterization with respect to morphology, chemical composition, structural, magnetic and optical properties. The microwave‐based approach offers a straightforward and one‐step access to nanostructured zinc gallate‐based materials and related compounds as a new preparative advantage. As the properties of mixed spinel‐based solid solutions strongly depend on the distribution of the guest ions between the different lattice sites, we have employed a wide range of analytical techniques to investigate the physico‐chemical properties of the obtained copper‐containing zinc gallate materials. The element specific EXAFS analysis at the Cu K‐ and Zn K‐edge shows a difference in the coordination environments with Zn mostly situated on the tetrahedral sites of the spinel lattice whereas Cu is located on the octahedral sites of the nanostructured ZnGa2O4:Cu2+ materials.

Oxide Nanomaterials: Synthetic Developments, Mechanistic Studies, and Technological Innovations

“…In the present case, copper gallium spinels were obtained with a straightforward MW-HT approach, but, in addition, this strategy also produced nanostructured materials which was recently demonstrated by some of us for coppersubstituted ZnGa 2 O 4 spinels. [137] Copper gallium spinels are interesting materials from the theoretical and technical point of view: the Cu 2+ ions which display the Jahn-Teller effect, are distributed within the "inert" gallium sublattice and they can be reductively transformed into nanoscale copper-catalysts that are embedded in the gallium matrix. Nevertheless, only few syntheses of copper gallium spinel phases have been reported to date, namely solid-state, [138] sol-gel, [139a] and a route to a spin-glass state.…”

Microwave Hydrothermal and Solvothermal Processing of Materials and Compounds

“…The synthesized CoAl2O4 particles were regular octahedrons measuring approximately 70 nm and were used to prepare an aqueous suspension, which was then used for printing on tiles by an ink-jet printing system. A convenient H-MW synthesis of nanostructured Cu 2+ -substituted ZnGa2O4 spinels was reported (Conrad et al, 2010). A difference was observed in the coordination environments with Zn mostly situated on the tetrahedral sites of the spinel lattice whereas Cu is located on the octahedral sites of the nanostructured ZnGa2O4:Cu 2+ materials.…”

Atomic spectrometry update. Industrial analysis: metals, chemicals and advanced materials

“…423 The technique of EXAFS was used to determine that Zn was coordinated mainly in the tetrahedral sites of the spinel lattice, whereas Cu was located in the octahedral sites. 423 The technique of EXAFS was used to determine that Zn was coordinated mainly in the tetrahedral sites of the spinel lattice, whereas Cu was located in the octahedral sites.…”