Platinum nanocatalyst could aid drug manufacturers
Chemists from Rice University in Texas in the US have developed a polymer-coated version of gold-platinum nanorods, the first catalysts of their kind that can be used in the organic solvents favoured by chemical and drug manufacturers.
Chemists from Rice University in Texas in the US have developed a polymer-coated version of gold-platinum nanorods, the first catalysts of their kind that can be used in the organic solvents favoured by chemical and drug manufacturers.
Nanoparticles combining platinum and gold act as super-efficient catalysts, but until now chemists have struggled to create them in an industrially useful form. "There are some industrial reactions where drugmakers have no choice but to use platinum and palladium catalysts, but the majority of these are homogenous, which means they mix readily with reactants and are very difficult to remove," said lead researcher Eugene Zubarev, associate professor in chemistry at Rice.
Zubarev and Rice graduate student Bishnu Khanal set out to make a heterogeneous platinum catalyst that was soluble enough for industrial use, but that could also be easily removed. Previous studies had shown that combining platinum with gold in nanoparticles could enhance the platinum's catalytic effect, so they started with tiny rods of pure gold and coated them with a layer of platinum so thin that it left the gold exposed in some places.
Building on Zubarev's previous work in making soluble gold nanorods, the researchers found a way to attach hair-like molecules of polystyrene to the surface of the gold-platinum rods. Not only were the coated particles easy to remove from solution with a conventional centrifuge, the polystyrene shells made them completely soluble in organic solvents and dramatically enhanced their catalytic selectivity.
"The selectivity of the coated gold and platinum nanorods will be very attractive to industry," Zubarev said. "For example, we found they had nearly 100% catalytic selectivity for the hydrogenation of terminal olefins."
The research is available online in the 1 September issue of the German scientific journal Angewandte Chemie International Edition.
Zubarev's group is using similar methods to produce gold-palladium catalysts in a follow-up study. "The early indications are very promising," he said.
