Researchers believe that the puzzle of catalytic gold is now partially solved. Gold can catalyse an oxidation reaction by first oxidising itself. New research evidence on gold-oxide phase at room temperature and atmospheric pressure help us to finally understand the oxidation mechanisms of catalytic gold nanoclusters in these conditions.
"This is vital if we want to design oxidation catalysts that could use ambient oxygen in the reaction process. Catalysts that function at low temperatures are significant in terms of energy efficiency in the future," says Academy Research Fellow Karoliina Honkala at the Nanoscience Centre (NSC) of the University of Jyvskyl.
The researchers at the NSC show new evidence from computational studies that supported nanometer-sized gold clusters can completely break the O-O bond by formation of a novel one-dimensional gold-oxide phase at the boundary of the cluster. This mechanism is predicted to dominate at ambient conditions of one atmospheric pressure and room temperature.
The study was published in September in Angewandte Chemie, the leading international journal in chemistry. The study is part of Karoliina Honkala's Academy of Finland Academy Researcher project and it was conducted in cooperation with Professor Hannu Hkkinen. The computational work was facilitated by extensive resources from the Finnish IT Center for Science, CSC.
In the study, researchers exposed the monolayer-thick gold clusters to a variable number of oxygen molecules. It was found that even one gold cluster can effectively adsorb multiple oxygen molecules at the boundaries of the cluster, simultaneously weakening (stretching) the O-O bond by transferring electrons to the oxygen molecules. Taking into account the effects of temperature and ambient pressure, the calculations predicted that the oxygen molecules will completely dissociate and the oxygen and gold atoms will form one-dimensional alternating chains at
|Contact: Hannu Hkkinen|
Academy of Finland