Take a ride on the University of Delaware’s Fuel Cell bus, and you will find out that fuel cells can power vehicles in an environmentally friendly way. In just the last two years, Toyota, Hyundai, and Honda have released vehicles that run on fuel cells, and carmakers such as GM, BMW, and Volkswagen are working on prototypes.
If their power sources lasted longer and cost less, fuel-cell vehicles could enter the mainstream faster. A team of engineers at the University of Delaware (Fig. 1) could turn that possibility into reality—they developed a technology that makes fuel cells cheaper and more durable.
The team describes their results in a paper published in Nature Communications. Authors include Weiqing Zheng, a research associate at the Catalysis Center for Energy Innovation; Liang Wang, an associate scientist in the Department of Mechanical Engineering (Fig. 2); Fei Deng, a research associate in materials science and engineering; Stephen A. Giles, a graduate student in chemical and biomolecular engineering; Ajay K. Prasad, Engineering Alumni Distinguished Professor and chair of the Department of Mechanical Engineering; Suresh G. Advani, George W. Laird Professor in the Department of Mechanical Engineering; Yushan Yan, Distinguished Engineering Professor in the Department of Chemical and Biomolecular Engineering and the Associate Dean for Research and Entrepreneurship for the College of Engineering; and Dionisios Vlachos, Allan and Myra Ferguson Professor of Chemical and Biomolecular Engineering and director of the Catalysis Center for Energy Innovation.
Cleaner energy, lower cost
Hydrogen-powered fuel cells are a green alternative to internal combustion engines because they produce power through electrochemical reactions, leaving no pollution behind. Materials called catalysts spur these electrochemical reactions.
Platinum is the most common catalyst in the fuel cells used in vehicles. However, platinum is expensive—the metal costs around $30,000 per kilogram.
So, the UD team turned to a catalyst of tungsten carbide, which goes for around $150 per kilogram. They were able to produce tungsten-carbide nanoparticles that are much smaller and more scalable than previous methods.
“The material is typically made at very high temperatures, about 1,500°C, and at these temperatures, it grows big and has little surface area for chemistry to take place on,” said Vlachos. “Our approach is one of the first to make nanoscale material of high surface area that can be commercially relevant for catalysis.”
The researchers made the tungsten-carbide nanoparticles using a series of steps, including hydrothermal treatment, separation, reduction, and carburization.
“We can isolate the individual tungsten-carbide nanoparticles during the process and make a very uniform distribution of particle size,” said Zheng.