Silver catalyzes hydrogen for cheap

In 1806, Swiss engineer François Isaac de Rivaz invented an internal combustion engine that used a mixture of hydrogen and oxygen as fuel. The first electric car came some 25 years later, long before the modern gas engine in 1885.

But then Henry Ford built the inexpensive Model T in 1908, with an internal combustion engine that ran on gasoline at an impressively low $280, while electric cars at their peak in 1912 sold for over $1,000.

Considering that hydrogen is the most plentiful element in the universe and the emissions from burning this gas are life-giving water vapor, this first element on the periodic table is making a comeback as fuel for vehicles and industrial processes.

Hydrogen can be extracted from several materials like natural gas and crude oil, but water is the only pollution-free source. Using an equally clean energy source like solar panels and wind turbines, the hydrogen and oxygen atoms in water can be separated by electrolysis. The resulting gas can be burned cleanly or compressed for storage and used in fuel cells.

Currently, the rare and expensive family of platinum group metals (especially iridium) have been the catalysts of choice, holding back the field of hydrogen production and fuel cells.

"Catalysts based on PGMs (platinum group metals) are used in a variety of applications such as chemical manufacturing, automotive catalytic converters, and petroleum refining. They are also central to emerging decarbonization technologies such as water electrolyzers for green hydrogen production and fuel cells for vehicles and stationary energy storage," said a DOE report. "To meet the nation's goal of net-zero carbon emissions by 2050, decarbonization of these energy and emissions intensive processes will be crucial."

Scientists at the U.S. Department of Energy's SLAC National Accelerator Laboratory, Stanford University, and the Toyota Research Institute have made a breakthrough with silver that could make it much cheaper and practical to produce hydrogen from water.

Silver lining

DOE is particularly interested in the efficient production of green hydrogen to decarbonize industrial processes like steelmaking in the U.S., which is estimated to produce a 1:1 ratio of carbon to steel tonnage.

Cheaper hydrogen fuel cells took a step closer to reality with a SUNCAT Center for Interface Science and Catalysis, a SLAC-Stanford joint institute, and the Toyota Research Institute discovery that could replace cost-prohibitive platinum group metal (PGMs) catalysts with silver.

Researchers often find a process that works in a small lab setup doesn't always scale to industrial applications.

To ensure the silver catalyst discovery could be scaled up, the research team worked with experts at Technion – Israel Institute of Technology, who successfully tested the method in a practical fuel cell.

"Hydrogen fuel cells have really great potential for energy storage and conversion, using hydrogen as an alternative fuel to, say, gasoline," said Michaela Burke Stevens, an associate scientist with SLAC and one of the senior authors on the study. "But it's still fairly expensive to run a fuel cell."

The collaborators found that by substituting cheaper silver for some of the PGMs used in previous catalysts, they could achieve an equally effective fuel cell with a much lower price tag and are gearing up to test more ambitious ideas.

"We could try going entirely PGM-free," said Tom Jaramillo, director of SUNCAT.

Research like this will determine whether hydrogen fuel cells can finally fulfill their long-promised potential.

"Fuel cells are really looking exciting and interesting for heavy-duty transportation and clean energy storage," said Jaramillo. "But it's ultimately going to come down to lowering cost, which is what this collaborative work is all about."