Due to its affordability and environmental friendliness, hydrogen is an attractive alternative to fossil fuels and battery-electric energy for many applications including transportation. However, because of its low density, hydrogen is difficult to transport efficiently, and existing onboard hydrogen generation methods are slow and energy-intensive.
Recently, a team of Chinese researchers made major progress in engineering a real-time, on-demand hydrogen generation system for use with fuel cells. They describe their results in the Journal of Renewable and Sustainable Energy.
The researchers used an alloy of gallium, indium, tin, and bismuth to catalyze a hydrogen-generating reaction. When this alloy meets an aluminum plate immersed in water, hydrogen is produced. When this hydrogen source was connected to a proton exchange membrane fuel cell, the chemical energy in the hydrogen was converted into electrical energy.
Compared with traditional methods of electric power generation, proton exchange membrane fuel cells have a very high conversion efficiency. They can start rapidly and run quietly. Moreover, the only waste product they generate is water, making them environmentally friendly.
The researchers found that the addition of bismuth to the alloy had a huge effect on hydrogen generation when compared to an alloy of gallium, indium, and tin without bismuth. Including bismuth in the alloy leads to a more stable and durable hydrogen generation reaction. Another important factor in the design of this hydrogen generation system is the ability to recycle the alloy. That helps minimize cost and environmental impact.
Before new hydrogen generators and fuel cells can become a commercial solution for transportation and other applications, several problems still need to be solved. For instance, existing methods for post-reaction mixture separation can cause corrosion and pollution problems and heat dissipation in the hydrogen reaction process also needs to be optimized.
Once these difficulties are resolved, this technology could be used for applications ranging from transportation to myriad portable devices.