Silver molybdate

Structure

Silver molybdate crystals present two types of electronic structure, depending on the pressure conditions to which the crystal is subjected. At room temperature, it exhibits a spinel-type cubic structure, known as β-Ag2MoO4, which is more stable in nature. However, when exposed to high hydrostatic pressure, the tetragonal α-Ag2MoO4 forms as a metastable phase.

Synthesis and properties

α-Ag2MoO4

α-Ag2MoO4 can be prepared by solution-phase precipitation under ambient conditions, using 3-bis(2-pyridyl)pyrazine (dpp) as a doping agent. The pH of the starting solution influences the growth and formation processes of distinct heterostructures (brooms, flowers and rods).

β-Ag2MoO4

β-Ag2MoO4 crystals can be prepared by solid-state reaction or oxide mixture at high temperature, melt-quenching, and Czochralski growth.

Additional methods include co-precipitation, microwave-assisted hydrothermal synthesis, a dynamic template route using polymerization of acrylamide assisted templates, and an impregnation/calcination method.

β-Ag2MoO4 microcrystals can be synthesized by precipitation employing polar solvents.

Photocatalytic properties of β–Ag2MoO4 crystals can be improved through hydrothermal processing at different temperatures. The replacement of Ag atoms with Zn to form silver-zinc molybdate [β–(Ag2−2xZnx)MoO4] microcrystals by a sonochemical method also leads to improvements. These crystals are able to degrade rhodamine B and Remazol Brilliant Violet 5R.

Ag-Ag2MoO4 composites

Ag-Ag2MoO4 composites can be prepared by microwave-assisted hydrothermal synthesis. These composites present photocatalytic activity for the degradation of rhodamine B under visible light.

Other properties

Ag2MoO4 mixed with graphite acts as a good lubricant for Ni-based composites, improving the tribological properties of the system.

References

References

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11. (2015-10-15). "Co-benefit of Ag and Mo for the catalytic oxidation of elemental mercury". Fuel.
12. (2015-10-28). "Structural, morphological and optical investigation of β-Ag 2 MoO 4 microcrystals obtained with different polar solvents". CrystEngComm.
13. (20 July 2018). "Hydrothermal synthesis, structural characterization and photocatalytic properties of β--Ag2MoO4 microcrystals: Correlation between experimental and theoretical data". Arabian Journal of Chemistry.
14. (2019). "Structural refinement, morphology and photocatalytic properties of β-(Ag_2−2''x''Zn_x)MoO₄ microcrystals synthesized by the sonochemical method". Journal of Materials Science: Materials in Electronics.
15. (2013-02-22). "Microwave-assisted hydrothermal synthesis of cube-like Ag-Ag2MoO4 with visible-light photocatalytic activity". Science China Chemistry.
16. (2013-03-24). "Friction and Wear Behaviors of Ni-based Composites Containing Graphite/Ag2MoO4 Lubricants". Tribology Letters.