Hydrogen fuel cells has a lot of advantage to the environment if it used to power up a vehicle as it promise to emit only water vapour instead of carbon dioxide. However, it is not easy to store a hydrogen gas. Recently, scientists at University of California, San Diego, suggested that they have solved the storage issue by using a 20-micron-wide particle that acts like self propelled micro motors.
Hydrogen fuel cells generate electricity by combining hydrogen and oxygen from the air to power up a vehicle and the only waste product that they emit is water vapour. Scientists has suggested to store these fuel cells in the form of liquids loaded with hydrogen contained salts such as sodium borohydride instead of storing raw hydrogen gas in a pressurized tanks.
These hydrogen contained salts will release hydrogen gas when exposed to metal catalyst in the form of either nanoparticles or thin films. However, this is considered not a really good solution as the release rate of hydrogen gas is limited by deactivation of the catalysts by poor mixing of fuel or accumulation of catalytic reactions by-products.
This is where the invention of the scientist at University of California could help. Their invention is a micro motor known as “Janus particles” which has two sides made from different material. One side is made of a very fine catalytically active platinum powder while the other is coated by titanium.
When these micro motors submerged in sodium borohydride solution, the platinum side will react with hydrogen loaded salt while the titanium side remains inactive. In the end, the platinum will produce hydrogen gas which eventually will push the micro particle around inside the fluid with speed roughly 250 micrometers per second.
The scientists demonstrate this behaviour in a small model car equipped with hydrogen fuel cells and their Janus particles and it is proven to work.