Catalytic gold nanoparticles could help speed up chemical reactions, which play a key role in mitigating environmental pollutants and producing specialty chemicals, according to researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL), US.

Scientists from Carnegie Mellon University and ORNL have found a gold molecule, a catalyst containing 25 gold atoms, which catalyses the conversion of various molecules such as the transformation of poisonous carbon monoxide into harmless carbon dioxide.

"Scientists from Carnegie Mellon University and ORNL have found a gold molecule, a catalyst containing 25 gold atoms, which catalyses the conversion of various molecules."

However, they found that ligands, which create and stabilise the engineered clusters, hinder the conversion process.

ORNL study lead Zili Wu said: "The ligands are double-edged swords.

"We’re interested in using gold clusters as catalysts or catalyst precursors. Ligands on the one hand stabilise the gold particle structure, but on the other hand decrease their catalytic performance.



"Balancing those two factors is the key to creating a new catalytic system.

"One way is to utilise a metal oxide (here, cerium oxide) as an inorganic ligand to stabilise the gold clusters when the organic ligand has to be removed for catalysis."

As part of their study, the researchers illustrated how ligands help in placing the gold nanocluster on a cerium oxide support shaped like a rod.

The ligands start to come off when the gold clusters are heated, and the gold’s catalytic activity increases.

Scientists plan to create novel uniform catalysts by varying the gold-cluster size and stabilising the new clusters.

ORNL catalysis group lead Steve Overbury said: "We want to understand how other kinds of reactions can be catalysed by these.

"Our primary interest is using the gold-nanocluster complex as a toolbox for learning about how other complex reactions occur.

"We’re only just starting to mine all the catalytic possibilities for gold."