Dec 1 2014
Tufts University researchers along with the researchers from other national laboratories and universities have developed new catalysts that could reduce the cost of fuels such as hydrogen.
The catalysts developed have a distinct formation with oxygen-bound gold atoms linked to potassium or sodium atoms. The structure of the catalyst was built on non-reactive silica materials.
In this study, published in the Science Express journal, the researchers have also demonstrated the comparative analysis of these catalysts with the precious metal nanoparticles catalysts supported over the reducible oxide substrates and used while producing highly purified hydrogen, in terms of stability and activity. The research findings could aid in the fabrication of single-site supported gold catalysts producing high-grade hydrogen for use in vehicles powered by fuel cells.
The research team was keen on developing catalysts that generate high-grade hydrogen using a lower amount of precious metals. The key process used is a water-gas shift reaction which involves eliminating carbon monoxide from the fuel gas stream upon reaction with water to form hydrogen and carbon dioxide. However, catalysts based on the oxide supported precious metals such as gold and platinum can be used to mitigate the reaction temperature and enhance the hydrogen production.
This research team was the first to observe that the atomically dispersed gold or platinum on substrate acts as the active site for the water-gas shift reaction. They pointed out that the single precious metal atoms with alkali ions are the critical sites for catalytic reactions. Therefore, the catalyst production process should depend solely on atomic dispersion over various substrates, avoiding particle formation.
The research focuses on the stabilization of single gold atoms on the silica-based non-reactive substrates using alkali ions. The precious metal tends to remain stable and operate for a long time with the stabilization of gold cations or atoms in a single-site form configuration.
One of the team members stated that maximum gold utilization rate and efficiency were obtained from this new atomic-scale catalyst configuration, which proved that the single-site gold cations remained stable even at high temperatures of 200°C. She added that this finding could also enable the scientists to design catalysts with the required amount of precious metals like gold and platinum, reducing the catalyst cost spent in the production of chemicals.
In the face of precious metals scarcity and exorbitant fuel-processing costs, these systems are promising in the search for sustainable global energy solutions.
Senior author Maria Flytzani-Stephanopoulos
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