Tehdyt toimenpiteet
Quantum-size effects in oxidization reactions catalyzed by gold clusters
26.03.2010
A research group led by Professor Hannu Häkkinen at the Nanoscience Center of the University of Jyväskylä has investigated the catalytic properties of miniscule gold atom clusters protected by ligands when ambient carbon monoxide is being oxidized to carbon dioxide.
Small nanoscale clusters of gold are known to act as efficient catalysts in oxidization reactions at room temperature and under normal pressure. The researchers investigated gold atom clusters over the size range of 1.2 – 2.4 nm (a nanometer equals a millionth of a millimeter). Using ab initio density functional calculations, they noticed that the size of the gold cluster and the quantum-range changes in its electron structure play a critical role in the decomposing, binding, and activating of the oxygen molecule contained in ambient air. Only the smallest (1.2 – 1.8 nm) gold clusters were able to bind oxygen molecules and significantly catalyze the oxidization reaction of carbon monoxide. The electron structure of larger clusters is closer to that on the surface of macroscopic gold, and macroscopic gold surfaces are inert (non-active).
The surface of small gold clusters is protected with ligands, i.e. small-sized compounds that bind with the surface, to stabilize the gold cluster. If the protection is removed even partially, it activates the catalyst. The study provides additional information about the stabilization and catalytic role of small gold clusters. The research suggests that there might be applications of environmental chemistry, where ligand-protected gold clusters could be built into energy-friendly and eco-efficient oxidization catalysts. Gold catalysts are active even at very low temperatures (-100◦C + 50◦C).
The results were published on March 24, 2010 in the highly respected Nature Chemistry journal. The supercomputing resources and GPAW software of CSC were utilized in the study. GPAW is an open source software package for quantum mechanical simulations. CSC developed GPAW in collaboration with Aalto University, Tampere University of Technology, the University of Jyväskylä, and the Technical University of Denmark.
More information
Olga Lopez-Acevedo, Katarzyna Kacprzak, Jaakko Akola and Hannu Häkkinen: Quantum size effects in ambient CO oxidation catalyzed by ligand-protected gold clusters. Nature Chemistry 2, 329 - 334 (2010)
CSC - IT Center for Science Ltd. is a non-profit limited company administered by the Ministry of Education. Having core competences in modeling, computing and information services, CSC provides versatile IT services, support and resources for academia, research institutes, and companies. CSC provides Finland's widest selection of scientific software and databases and Finland's most powerful supercomputers that researchers can use via the Funet network.
