Kyushu University research group develops new method for creating highly efficient gold nanoparticle catalysts for fuel cells
A team of researchers at Kyushu University’s International Institute for Carbon-Neutral Energy Research (I2CNER) reports devising a method for using a new type of catalyst support for highly active gold nanoparticle catalysts for fuel cells. An open access paper on the work is published in Scientific Reports.
In the search for non-platinum electrocatalysts for fuel cells, gold nanoparticles (Au-NPs) have attracted a great deal of interest due to their very high catalytic activity for the oxygen reduction reaction (ORR), despite the inertness of bulk gold. Further, small-sized Au-NPs have been shown to have excellent tolerance to methanol oxidation—meaning that methanol poisoning can be ignored, an ideal attribute for practical applications, especially in the cathode in the direct methanol alkaline fuel cells.
However, actually creating uniformly sized gold nanoparticle catalysts has proven problematic. Previous fabrication methods have produced catalysts with nanoparticle sizes that were too large or too widely distributed for practical use. Meanwhile, efforts to regulate the particle size tended to restrict the gold’s activity or make less-stable catalysts.
The researchers wrapped a graphene support in a specially prepared polymer to provide an ideal foundation for making uniform, highly active gold nanoparticle catalysts.
|A polybenzimidazole polymer supports the formation of gold nanoparticles with well-defined sizes on graphene. Credit: International Institute for Carbon-Neutral Energy Research (I²CNER), Kyushu University. Click to enlarge.|
Creating small, well-controlled particles meant that we needed to focus on particle nucleation and particle growth. By wrapping the support in the polybenzimidazole polymer we successfully developed with platinum, we created a much better support environment for the gold nanoparticles.—lead and corresponding author Tsuyohiko Fujigaya
The team also tested the performance of these novel catalyst structures. Their catalysts had the lowest overpotential ever reported for this type of reaction.
The overpotential is a bit like the size of the spark you need to start a fire. Although we’re obviously pleased with the catalysts’ uniformity, the performance results show this really could be a leap forward for the ORR reaction and maybe fuel cells as well.—Naotoshi Nakashima
Although novel in its own right, this recent publication is the latest in a chain of developments that the interdisciplinary teams at I2CNER have been carrying out to develop fuel cells and other clean technologies.The array of technologies that I2CNER’s research aims to enable includes Solid Oxide Fuel Cells, Polymer Membrane based fuel cells, biomimetic and other novel catalyst concepts, and production, storage, and utilization of hydrogen as a fuel.
Tsuyohiko Fujigaya, ChaeRin Kim, Yuki Hamasaki & Naotoshi Nakashima (2016) “Growth and Deposition of Au Nanoclusters on Polymer-wrapped Graphene and Their Oxygen Reduction Activity” Scientific Reports 6, Article number: 21314 doi: 10.1038/srep21314