Processes that store renewable energy such as wind or solar energy as chemical fuels have the potential to provide a substitute for fossil fuels and ease civilization’s reliance on non-renewable resources. However, technologies that generate hydrogen and oxygen from water currently are so energy inefficient that the process is commercially limited as a means of converting solar energy to hydrogen gas as fuel or chemical feedstock. To drive this electrolysis reaction, a substantial amount of energy over the theoretical minimum required must be provided. This extra energy is known as the overpotential. 

Efforts to reduce the overpotential have improved the process, but significant obstacles to commercial use remain, including requirements for elevated temperatures, highly basic environments or expensive catalysts. More efficient water-electrolysis catalysts for the conversion of water to hydrogen and oxygen are needed.

UW-Madison researchers have developed an improved catalytic method for generating hydrogen and oxygen gas via water electrolysis. The method uses novel electrocatalysts formed from cobalt, oxygen and fluoride. These unique catalysts result in an electrolysis reaction with a favorable shift in pH tolerance and altered overpotential, making it easier and less expensive to split water into hydrogen and oxygen and providing a more practical means of storing renewable energy.

To drive the electrolysis reactions, electricity can be generated using a renewable energy source such as a solar cell or wind turbine. The hydrogen gas that results from this process can be collected and used as an alternative fuel source for vehicles or other fuel-dependent applications or as a feedstock for conversion into other fuels or materials. The oxygen gas can be collected and used for any process that requires pure oxygen, such as steelmaking.

File Number: P100096US01