More efficient fuel-cells, thanks to a new catalyst

This release is available in Spanish.

Over the past decades climate change and its consequences for life on our planet have given rise to a growing scientific interest in the development of alternative energies. The fossil fuels that currently dominate our energy map are not only becoming scarce, but are moreover generating large quantities of contaminating gases. Within the field of renewable energies the scientific community is today devoting great efforts to investigating and developing fuel cells, capable of creating electrical energy from a chemical reaction between a fuel and oxygen.

For fuel cells to be a competitive option amongst alternative energies, advances in a number of fields are required, amongst these being the development of new catalysts, i.e. substances that are responsible for accelerating the chemical reaction required for electricity to be produced. It is in here that José E. Barranco’s focused when he presented his PhD thesis, Development of new metallic materials of an amorphous nature for use in direct methanol fuel cells, at the UPV/EHU. José Enrique Barranco Riveros is a graduate in Chemical Sciences and is currently working as a researcher employed by the Polytechnic University School in the Basque city of Donostia-San Sebastián. His PhD was awarded excellent cum laude unanimously and was led by Dr. Ángel Rodríguez Pierna of the Department of Chemical Engineering and the Environment at the University School.

Methanol as an alternative

Most current research is focused on hydrogen cells the biggest advantage of which is that they do not generate contaminant gases, except water vapour as the only waste product. However, hydrogen is very expensive, both in producing it and in distributing it using traditional overland transport methods. Moreover, its energy density is less than that of methanol, meaning that, in order to obtain the same energy from a similar amount of fuel, the hydrogen has to be kept and stored under conditions of very high pressure (more than 800 bars). This is why hydrogen is dangerous, and even more so when stored in vehicles travelling at high speed – a small crack in the storage container could have fatal consequences. These and other reasons mean that methanol (a type of alcohol derived from methane gas) is a good option for charging fuel cells.

More efficient and sustainable catalysts

In order for the fuel cell to generate electricity, a chemical reaction called electro-oxidation has to take place and this, in turn, requires a catalyst to accelerate the process. This catalyst is inserted in the fuel cell membrane and, in the case of methanol, the basic accelerator is platinum, a scarce and expensive metal. This is why the aim of Dr. Barranco’s thesis was to devise a catalyst composed of a metal alloy in which the amount of platinum is significantly reduced. His research focused on a fundamental problem: the electro-oxidation of methanol produces carbon monoxide, a molecule that adheres to the metal and inhibits the latter’s catalysing capacity, i.e. it impedes the accelerator from doing its work and energy production is halted.