Fuel cells that convert hydrogen into power and only produce pure water as a by-product have the potential to lead individual mobility into an environmentally friendly future. The Paul Scherrer Institute (PSI) has been researching and developing such low-temperature polymer electrolyte fuel cells for more than 10 years and initial field tests have already demonstrated the successful use of these fuel cells in cars and buses. However, further research is still required to improve the durability and economic viability of the technology. An international team of researchers involving the PSI has now manufactured and characterised a novel nanomaterial that could vastly increase the efficiency and shelf-life of these fuel cells – as well as reduce material costs.
In a hydrogen fuel cell, hydrogen is converted into power and water through electrochemical reactions. A key step in these reactions is the reduction of oxygen at the cell’s positive electrode, where oxygen molecules fed into the cell are converted into water. As this reaction takes place very slowly under normal conditions, catalysts are needed to speed up the conversion process. In conventional cells, precious metals such as platinum fullfill this catalytic function. The thin nanoparticles used for this purpose are supported by a substrate typically made of high surface area carbon. However, the carbon substrate can easily become corroded during the common start/stop operation in city traffic or during idling; thereby compromising the function of the catalyst, which in turn shortens the service life of the entire fuel cell. Consequently, researchers have long been looking for catalysts for oxygen reduction that do not need a support and still display a high specific surface area with a large number of catalytic centres as well as good long-term stability.
Read more at: Phys.org