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Synthesis of silver molybdate clusters driven by laser-annealing
C Bréchignac1, Ph Cahuzac, N Kebaili
1Laboratoire Aimé Cotton, Bât 505, Campus d'Orsay, F-91405 Orsay Cedex, France. catherine.brechignac@lac.u-psud.fr
The Journal of Chemical Physics
|November 13, 2004
Summary
Researchers synthesized silver-rich molybdate clusters using laser-induced reactions of molybdenum trioxide and oxygen on silver clusters. This method creates stable binary oxides with unique compositions in small clusters.
Area of Science:
- Materials Science
- Cluster Chemistry
- Surface Science
Background:
- Free silver clusters serve as substrates for chemical reactions.
- Understanding metal-oxygen interactions is crucial for materials synthesis.
Purpose of the Study:
- To synthesize silver-rich molybdate clusters.
- To investigate the role of coadsorbed MoO(3) and O(2) on silver clusters.
- To analyze the composition and stability of synthesized clusters.
Main Methods:
- Condensation of MoO(3) and/or O(2) on free silver clusters at low temperatures (77 K-175 K).
- Ionization and laser heating of adsorbed molecules on silver clusters.
- Analysis of synthesized compounds using high-resolution time-of-flight mass spectrometry.
- Cooling of synthesized species by silver atom evaporation.
Main Results:
- Single reactant adsorption leads to one stabilized oxide molecule.
- Co-adsorption of MoO(3) and O(2) on Ag(n)(+) results in molybdate-rich metal clusters after laser heating.
- Synthesized binary oxides are more stable than the metallic core.
- Small molybdate clusters exhibit stoichiometric compositions that differ from bulk materials.
Conclusions:
- Laser-induced reactions provide a pathway for synthesizing novel silver-molybdate clusters.
- The co-adsorption of MoO(3) and O(2) is key to forming stable molybdate-rich clusters.
- Cluster size significantly influences the stoichiometry of metal oxides.