Hydrogen is a promising chemical and energy vector to decarbonize our society. Unlike conventional fuels, hydrogen utilization as a fuel does not generate carbon dioxide in return. Unfortunately, today, most of the hydrogen that is produced in our society comes from methane, a fossil fuel. It does so in a process (methane reforming) that leads to substantial carbon dioxide emissions. Therefore, the production of green hydrogen requires scalable alternatives to this process.
Water electrolysis offers a path to generate green hydrogen which can be powered by renewables and clean electricity. This process needs cathode and anode catalysts to accelerate the otherwise inefficient reactions of water splitting and recombination into hydrogen and oxygen, respectively. From its early discovery in the late 18th century, water electrolysis has matured into different technologies. One of the most promising implementations of water electrolysis is the proton-exchange-membrane (PEM), which can produce green hydrogen combining high rates and high energy efficiency.
To date, water electrolysis—and in particular PEM—has required catalysts based on scarce, rare elements, such as platinum and iridium, among others. Only a few compounds combine the required activity and stability in the harsh chemical environment imposed by this reaction. This is especially challenging in the case of anode catalysts, which have to operate in highly corrosive acidic environments—conditions where only iridium oxides have shown stable operation at the required industrial conditions. But iridium is one of the scarcest elements on Earth.
In the search for possible solutions, a team of scientists has recently taken an important step to find alternatives to iridium catalysts. This multidisciplinary team has managed to develop a novel way to confer activity and stability to an iridium-free catalyst by harnessing so far unexplored properties of water. The new catalyst achieves—for the first time—stability in PEM water electrolysis at industrial conditions without the use of iridium.
To read more, click here.