Engineers have found a way to make fuel cells less expensive and more durable, a new research study finds. In an article published in Nature Communications on Monday, September 4, University of Delaware researchers Weiqing Zheng, Liang Wang, Fei Deng, Stephen Giles, Ajay Prasad, and others, reported the development of tungsten carbide as a new and cheaper catalyst for hydrogen-powered engines.
Hydrogen-powered fuel cells have been developed in recent years to provide an alternative to the internal combustion engine. Rather than releasing nitrogen and other fossil fuels into the air as waste, the fuel cells create an electrical charge. This is done by combining the hydrogen in the engine with the oxygen in the air. Water is the vehicle’s only waste.
Car giants Toyota, Hyundai, and Honda have been using fuel cells to power new eco-friendly vehicles over the past two years. However, the catalysts used to speed up the chemical reaction in the engine are often incredibly expensive, making it difficult for fuel cell vehicles to become mainstream. Platinum, the most popular fuel cell catalyst, is $30,000 a kilogram.
However, tungsten carbide is a hard metal available in a variety of grades that can be used for any number of applications. It’s also only $150 a kilogram.
“The material is typically made at very high temperatures, about 1,500 Celsius, and at these temperatures, it grows big and has little surface area for chemistry to take place on,” said Dionisios Vlachos, a researcher with the Catalysis Center for Energy Innovation. “Our approach is one of the first to make nanoscale material of high surface area that can be commercially relevant for catalysis.”
The researchers were able to produce tungsten carbide nanoparticles in a way that is more scalable and far smaller than engineers have been able to develop in the past. According to Science Daily, the process includes hydrothermal treatment, reduction, separation, carburization, etc, and results in the isolation of the tungsten carbide nanoparticles to be incorporated into the membrane of the fuel cells.
“The tungsten carbide catalyst improves the water management of fuel cells,” said Wang, “and reduces the burden of the humidification system.”
The polymeric membrane of an automotive fuel cell is what causes the cathode and anode to be separated. The anode splits the hydrogen into ions and then delivers the ions to the cathode, which creates the electric current to run the engine.
However, the polymeric membrane can wear down because of the humidity created between the heat of the vehicle and the water produced by the chemical reaction. The tungsten carbide, when added to the membrane, humidifies the membrane to keep it from degrading while also capturing any damaging free radicals.
“This is a very good example of how different groups across departments can collaborate,” said Zheng of the research team.
The UD researchers have applied for a patent for their new tungsten carbide technology and hope to use it for the future development of eco-friendly commercial vehicles.
