Catalysts in Hydrogen Fuel Cells Electrochemical energy conversion
Professor Boniface Kokoh is a chemist researcher and professor at the Poitiers Chemistry Institute: Materials and Natural Resources. The focus of his research is on Electrochemistry and Electrocatalysis of novel materials using ex situ and in situ techniques, fuel generation, interfacial characterization and surface analytical techniques. That might sound like Greek to most biologists, but in a nutshell, he is mostly interested in developing new materials that can be applied to green energy production such as hydrogen fuel cells in vehicles. We were fortunate to have Prof Boniface Kokoh to speak to us in a seminar regarding the development of fuel cells and its fuel: hydrogen. We also had a discussion on how the challenge lies on the cost of the catalysts which are required for the production of hydrogen gas.
A fuel cell is formed by a positive and a negative electrode, separated by an electrolyte membrane through which hydrogen ions can pass. Hydrogen is supplied to the negative electrode, and in the presence of a metal catalyst electrons are freed from the hydrogen molecules. The electrons flow through the circuit from the negative to the positive electrode. Meanwhile, the hydrogen ions pass through the electrolyte membrane where they combine with oxygen and the electrons to form water, which is the only emission from the reaction! Each cell produces a small voltage (1V or less), so in cars there are usually around 400 cells connected together in series to form the fuel cell stack.
Since molecular hydrogen is not naturally available, the next challenge is how to produce it in a cheap and clean way so that it can be stored in tanks and fed into fuel cell to produce electricity as needed. There are various methods to produce hydrogen gas including the use of fossil fuels in a process called thermolysis or via water electrolysis powered by solar cells. The former method still produces many environmental consequences and further depletes the already finite fossil fuel resources. Therefore, research should focus on improving hydrogen production via electrolysis of water. For this process, a catalyst (usually Dimensionally Stable based on noble metal) is used to lower the amount of electricity that is needed to produce hydrogen and oxygen from water. The cost of producing the catalysts for the electrolysis process is also one of the main barrier blocking wide-scale use of fuel cells. Furthermore, the challenge of using fuel cells is on how to increase the area of active sites on the surface and decrease the noble metal loading on the electrocatalyst. Nonetheless, research on this topic has been expanding due to the depletion of fossil fuels, gasoline pollution and greenhouse effect and there is a pressing need for the development of cleaner alternative sources of energy.
Some examples of fuel cells include the hydrogen powered vehicles such as the Toyota Mirai launched in Japan in 2014. You can visit this link to find out more about how a hydrogen powered vehicle works:
This talk not only widened our perspectives on how environmental issues are being tackled by scientists from different areas and fields, it also suggests that environmental issues are beyond the usual reliance on legislations for management. Sound scientific researches like those of fuel cells and other renewable energy sources should be the way forward, in addition to the top priority of changing the public’s mindset and increasing awareness on energy usage. As ecologists, we are sometimes too fixated on environmental issues pertaining to habitat losses and extinction of species. But because environmental issues are often complex, it is inspiring to know of other multidisciplinary approaches to find a solution, even if it was not direct one towards conserving biodiversity.
Written by Amanda and Jessica