Fabrication of heterogeneous catalysts by a laser technique
Ina Haxhiaj, University of Duisburg-Essen, Essen, GermanySebastian Kohsakowski, University of Duisburg-Essen, Essen, GermanySven Reichenberger, University of Duisburg-Essen, Essen, GermanyGalina Marzun, University of Duisburg-Essen, Essen, GermanyStephan Barcikowski, University of Duisburg-Essen, Essen, Germany
Surfactant-free metal nanoparticles fabricated by laser ablation in liquids are promising materials for energy converting materials like heterogeneous catalysts . Conventional preparation techniques of heterogeneous catalysts, like colloidal deposition or impregnation, usually require the use of chemical precursors and organic ligands for nanoparticle stabilization. This can lead to poising of the catalysts or their deactivation.
Laser ablation in liquids gives access to catalytic active, colloidal stable and nanoparticle size-controlled materials (e.g. Pt, Au, Pd). With this laser technique, it is possible to produce even alloy nanoparticles like AuAg, FeNi and NiMo with different composition ratios which cannot be easily produced by chemical route . For the ablation process, an intensive pulsed laser beam is focused onto an immersed target of the selected material. Hereby, properties of the pure, colloidal nanoparticles, like particle size and colloidal stability, can easily be controlled by the use of saline solutions .
For the fabrication of the heterogeneous catalysts we support laser-fabricated nanoparticles onto carrier structures like metal oxides (e.g. TiO2, ZnO) and carbon allotropes. The adsorption process of the nanoparticles is induced by electrostatic interactions . First tests of the laser-generated nanomaterials proved its catalytic activity and application potential. Gold nanoparticles on titanium dioxide showed a higher long time stability and activity for the selective ethanol oxidation than commercial catalyst at high temperature conditions .
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