10/12/2022
By Brooke Coupal

With 290 deployable ships and more than 3,700 aircraft, the U.S. Navy uses tremendous amounts of fuel.

The Defense Logistics Agency, which provides energy to military services, the Department of Defense and other federal agencies, reported in 2021 that it sold roughly 3.65 billion gallons of fuel to its customers, about a quarter of which went to the U.S. Navy. The agency manages several fuel products, ranging from petroleum to alternative fuels.

An alternative fuel that has piqued the U.S. Navy's interest is hydrogen, which is beneficial because it can be produced on demand and does not emit greenhouse gases, only water. However, the cost of producing hydrogen can be prohibitively expensive.

Chemistry Asst. Prof. Michael Ross is exploring ways to change that.

Ross was recently awarded a two-year, $363,211 Office of Naval Research grant to study new materials for making hydrogen.

At present, platinum is often used to make hydrogen, but the rare metal is expensive. Platinum is also limited in the way that it can produce hydrogen because for the reaction to work efficiently, it is typically used with an acidic solution, meaning the solution has a low pH level.

Under the new grant, Ross is searching for materials that can produce hydrogen in a variety of pH conditions.

“Platinum is currently the best at making hydrogen, but it’s used in a really narrow set of pH conditions,” says Ross, the grant’s sole principal investigator. “We want to identify characteristics of other materials to see how they work in various pH conditions to make hydrogen. Ideally, those materials will be less scarce, less expensive and more versatile than platinum.”

Ross will be studying different metal and metal alloys, as well as two-dimensional materials like carbides and selenides, to understand which characteristics make a material better or worse at producing hydrogen at different pH levels.

To study the materials’ effectiveness, Ross will be submerging them in water before applying electrical energy to generate hydrogen. The water will contain varying amounts of ions, which changes the acidity of the liquid and thus alters its pH level.

“We can independently control the pH variable and then study the same material in different pH conditions to learn how it behaves, how it performs and how stable it is,” he says.

The research will provide a framework for comparing materials across pH levels.

“Right now, we don’t have a specific way to compare a single material in a variety of pHs, so we want to develop that basic science,” he says.

Ross will also analyze how much hydrogen each material produces.

“Ideally, we will have a star material that will be effective at making hydrogen in a variety of pH conditions,” he says.

A postdoctoral fellow and multiple undergraduate students will assist Ross with the research. He says having students work in his lab benefits the project.

“Generally, they don’t have preconceived notions that scientists like me who have worked in the field for years have,” he says. “So, sometimes they’ll have creative ideas, which can lead the study in new directions.”