Green Hydrogen Breakthrough Sees Water Turned to Energy at Room Temperature

Scientists say they have found a new way to generate hydrogen gas from water at room temperature in what could be a step toward a clean and renewable energy source.

Hydrogen has been researched as a type of fuel or energy source for years. The modern hydrogen fuel cell, which can power anything from laptop computers to car batteries and power stations, works by combining hydrogen and oxygen atoms in a process that creates water, electricity and a small amount of heat.

As of the end of October 2021, hydrogen fuel cell power generators produced about 260 megawatts of electricity capacity across the United States. By comparison, the average wind turbine produced about 2.75 megawatts in 2020.

Hydrogen pipe
An industrial pipe with hydrogen running through the countryside. Hydrogen can be used in fuel cells to produce power, but the element is often made through nonrenewable processes. A discovery announced by University of California, Santa Cruz researchers could change that. Petmal/Getty

Despite its relatively low uptake, hydrogen has been hailed as a green solution to energy woes. But that's not the case today.

While hydrogen is the most abundant element in the universe, we still need to produce it for use in fuel cells. The problem is that about 95 percent of hydrogen is produced from a process involving natural gas, according to the U.S. Office of Energy Efficiency and Renewable Energy, and that process is not renewable.

There may be a solution to this particular problem, however. Researchers at the University of California, Santa Cruz (UCSC) have found a way to produce hydrogen by developing a special type of aluminum composite that reacts with water at room temperature.

On its own, aluminum is a reactive material that splits oxygen away from water molecules, leaving hydrogen gas behind.

Aluminum won't necessarily do this on its own, however. That's because at room temperature the metal forms a layer of aluminum oxide, which essentially protects it from reacting with water.

What scientists have discovered is that by using an easily produced composite of gallium and aluminum, it is possible to get this material to react with water at room temperature, producing hydrogen.

"We don't need any energy input, and it bubbles hydrogen like crazy," said UCSC chemistry professor Scott Oliver in a university press release. "I've never seen anything like it."

The fact that this aluminum-gallium mixture produces hydrogen has been known for decades. But what the UCSC team found was that increasing the concentration of gallium in the composite also increased the production of hydrogen.

"Our method uses a small amount of aluminum, which ensures it all dissolves into the majority gallium as discrete nanoparticles," Oliver said.

What's more, the composite can be made with easily accessible aluminum sources like foil or cans.

The downside is that gallium is relatively expensive, although it can be recovered in this process and reused multiple times. Another downside is that there is still no widespread uptake of hydrogen fuel cells. While it is possible to burn hydrogen directly as a fuel, it can be hazardous, and tanks often must be highly pressurized to contain useful amounts of it.

It remains to be seen if the UCSC process can be scaled up for the commercial production of hydrogen.

The findings were reported in a study published February 14 in the journal ACS Applied Nano Materials and writtenby Oliver, Bakthan Singaram and their colleagues.