Methanol fuel cells are an efficient and sustainable alternative tofossil fuels, but they are still not economically viable. Nevertheless,for his PhD, University of the Basque Country (UPV/EHU) researchchemist, José E. Barranco, has developed new materials that enable themanufacture of cheaper and more efficient methanol fuel cells.
                                                                                                                                               
                                Over the past decades climate change and its consequences for lifeon our planet have given rise to a growing scientific interest in thedevelopment of alternative energies. The fossil fuels that currentlydominate our energy map are not only becoming scarce, but are moreovergenerating large quantities of contaminating gases. Within the field ofrenewable energies the scientific community is today devoting greatefforts to investigating and developing fuel cells, capable of creatingelectrical energy from a chemical reaction between a fuel and oxygen.
For fuel cells to be a competitive option amongst alternativeenergies, advances in a number of fields are required, amongst thesebeing the development of new catalysts, i.e. substances that areresponsible for accelerating the chemical reaction required forelectricity to be produced. It is in here that José E. Barranco’sfocused when he presented his PhD thesis, Development of new metallicmaterials of an amorphous nature for use in direct methanol fuel cells,at the UPV/EHU. José Enrique Barranco Riveros is a graduate in ChemicalSciences and is currently working as a researcher employed by thePolytechnic University School in the Basque city of Donostia-SanSebastián. His PhD was awarded excellent cum laude unanimously and wasled by Dr. Ángel Rodríguez Pierna of the Department of ChemicalEngineering and the Environment at the University School.
Methanol as an alternative
Most current research is focused on hydrogen cells the biggestadvantage of which is that they do not generate contaminant gases,except water vapour as the only waste product. However, hydrogen isvery expensive, both in producing it and in distributing it usingtraditional overland transport methods. Moreover, its energy density isless than that of methanol, meaning that, in order to obtain the sameenergy from a similar amount of fuel, the hydrogen has to be kept andstored under conditions of very high pressure (more than 800 bars).This is why hydrogen is dangerous, and even more so when stored invehicles travelling at high speed – a small crack in the storagecontainer could have fatal consequences. These and other reasons meanthat methanol (a type of alcohol derived from methane gas) is a goodoption for charging fuel cells.
More efficient and sustainable catalysts
In order for the fuel cell to generate electricity, a chemicalreaction called electro-oxidation has to take place and this, in turn,requires a catalyst to accelerate the process. This catalyst isinserted in the fuel cell membrane and, in the case of methanol, thebasic accelerator is platinum, a scarce and expensive metal. This iswhy the aim of Dr. Barranco’s thesis was to devise a catalyst composedof a metal alloy in which the amount of platinum is significantlyreduced. His research focused on a fundamental problem: theelectro-oxidation of methanol produces carbon monoxide, a molecule thatadheres to the metal and inhibits the latter’s catalysing capacity,i.e. it impedes the accelerator from doing its work and energyproduction is halted.
After investigating the composition of numerous metals, Dr. Barrancomade alloys that enabled the reduction of the proportion of platinum to1%. These alloys, composed of elements such as nickel, niobium,antimony or ruthenium, amongst others, have the unique property ofconverting molecules of carbon monoxide (CO) into carbon dioxide (CO2)efficiently. The CO2, being gaseous, does not adhere to the catalystwhich in the long term favours the catalytic process.
This means that the methanol fuel cell will emit a small quantity ofCO2 which, according to Dr. Barranco, is easily tolerable by naturegiven that this can be incorporated into the photosynthesis cycle ofplants. According to a study by the American Methanol Institute, it isforecast that, by the year 2020, there will be 40 million cars poweredby methanol fuel cells, meaning that CO2 emissions will be cut by 104million tons with respect to emissions from petrol.
Catalysts in powder form
Once the suitable catalyst was found, Dr. Barranco set out toincrease its efficiency. The conclusions of his PhD thesis point to thefact that, if the platinum alloy is structured amorphously, itselectrical conduction properties are enhanced and it undergoes lesscorrosion (advantages for the medium in which it has to operate).Moreover, it has an operational capacity in the order of 80-100 timesgreater than platinum in a crystalline structure. Amorphous materialsare those with a disordered molecular structure and which, in thiscase, are obtained by the sudden cooling of metal alloys.
Also, for the catalyst made on this basis of amorphous metal alloysto be incorporated into the fuel cell membrane, Dr. Barranco decided tochange its form. The result is a very fine powder that is placed in acontainer to “spray paint” the membrane. Not only this: as it is asubstance made of minute particles, the operating capacity of thecatalyst is enhanced by 9 to 13 times.
Looking to a fuel cell completely built at the UPV/EHU
Taking into account that the catalyst improves the efficiency of thecell by more than 50%, this new material developed at the UPV/EHU is agiant step forward in fuel cell research. But the PhD thesis of MrBarranco is not limited to describing and producing the new catalyst.His work falls within the remit of the overall Alcohols Oxidation FuelCell Research being undertaken at the Industrial Chemistry andElectrochemical Engineering Laboratory of the Polytechnic UniversitySchool in Donostia-San Sebastián, research work being led by Dr. ÁngelRodríguez Pierna the target of which is to achieve a methanol fuel cellsolely and totally devised and developed at this laboratory.