An efficient iron-based fuel cell catalyst has been discovered by PNNL scientists. It uses a hydrogenase molecule to split hydrogen and create electricity.
For years, scientists have been playing around with various alternatives to platinum, an expensive catalyst used in hydrogen fuel cells today to create electricity directly from hydrogen.
Fortunately, platinum has the intrinsic property of splitting hydrogen gas and taking its electron to form an electrical current. However, platinum is some 1,000 times more expensive than iron or nickel, hence iron cannot be used as a drop-in replacement to it.
“A drawback with today’s fuel cells is that the platinum they use is more than a thousand times more expensive than iron,” said chemist R. Morris Bullock, who leads the research.
The scientists at DoE’s Pacific Northwest National Laboratory (PNNL) have used a naturally-occurring molecule called “hydrogenase” that uses iron to split hydrogen just the way platinum does, and with a comparable efficiency. Their result is the first iron-based fuel cell catalyst that converts hydrogen directly to electricity.
Their current version of the iron-based fuel cell catalyst can split two molecules per second and has an efficiency that’s close to commercially-available (platinum) catalysts.
Bullock’s team split the hydrogen atoms into pieces by using the hydrogenase catalyst, which moves the hydrogen molecule’s proton in one direction and the electron in the other direction, to the electrical circuit.
The complete chemical process you can find here, but the bottom line is that the iron-based fuel cell catalyst the team created processed two molecules per second, which is thousands of times quicker than the closest iron-based competitor. The voltage the fuel cell produced was 160 to 220 mV, which tells that the conversion efficiency is similar to what you can find on the market (only slower).
Future tasks include a method to make the process faster and to determine the iron-based catalyst’s ideal working conditions. No word on a possible commercial version.