Nanostructure catalysts could save pharma time & money

Researchers believe they are a step closer to creating superefficient industrial catalysts after a team made platinum-on-gold bimetallic nanorods that are soluble in organic solvents.

The research, which was published online in the September 1 edition of Angewandte Chemie, potentially opens up a new field of catalyst technology that could cut costs and time for pharmaceutical manufacturers.

Earlier research recognised the promise of bimetallic platinum-on-gold and palladium-on-gold nanostructures. The presence of gold nanoparticles is believed to enhance the effectiveness of the platinum catalysts, which are used because of their ability to cleave pairs of hydrogen atoms.

The nanoparticles could also improve the process because platinum and palladium generally mix readily with the reactants and this makes them difficult to remove, adding time and cost to the production process.

However, research into the use of the nanostructures has been restricted by the inability to create a catalyst that is soluble in organic solvents, which numerous reactions in drug production are performed in.

New research by scientists at Rice University, Texas, US attempted to overcome this problem. The team coated gold rods with a thin layer of platinum, leaving some areas of gold exposed, and attached hair-like molecules of polystyrene to the surface.

These structures have numerous benefits, according to the researchers. Firstly, the combination of platinum and gold could improve the effectiveness of the catalyst.

Furthermore, the addition of polystyrene molecules made the nanostructures soluble in organic solvents and enhanced catalytic selectivity. The researchers claim the nanostructures had nearly 100 per cent catalytic selectivity for the hydrogenation of terminal olefins.

Once the reaction is complete the catalysts can be removed using a centrifuge, which represents an improvement on current techniques for separating platinum from the reactants.

The researchers now plan to investigate the capabilities of the platinum nanostructures in catalysing reactions in organic media.