Researchers at the University of Michigan claim to have found a way to produce hydrogen for hydrogen fuel cell electric vehicles (HCEVs) in an efficient and affordable way.
Hydrogen has the potential to replace gasoline in internal combustion engines because it is clean, non-toxic and renewable. However, there is a slight problem with the mass production of hydrogen to replace gasoline.
Currently, gas is generated either through electrolysis or natural gas. Both methods have their drawbacks. A more efficient way to produce hydrogen is to use the sun, and Michigan researchers have done just that.
Michigan researchers have perfected a process called artificial photosynthesis. They successfully produced hydrogen more efficiently than the natural photosynthesis that plants use.
This process uses semiconductor catalysts. It takes a huge amount of heat to speed up the process and stop the oxygen and hydrogen recombining. Unfortunately, existing semiconductors cannot handle the heat required in the process.
The Michigan researchers also tackled this problem by shrinking the semiconductors by over 100 times.
They also used self-healing semiconductor technology and performed the process in a light source 160 times more intense than sunlight.
The artificial photosynthesis process perfected by the Michigan researchers uses one part of the light source to heat water and the other to break water molecules, resulting in more hydrogen and increased efficiency.
How does it work?
The Michigan researchers conducted two experiments to test the improved artificial photosynthesis process.
In one of the experiments, hydrogen and oxygen gases were released from a semiconductor catalyst, which had a layer of water on it, using natural light that was intensified by a lens similar in size to a window.
This experiment was conducted outdoors. The semiconductor was made from indium gallium nitrate, grown on a silicon surface.
In the outdoor test, the artificial photosynthesis achieved a 6.1% efficiency in converting water to hydrogen, which is significantly more efficient, almost 10 times, than previous solar water splitting experiments. Its efficiency increased to 9% when the same process was repeated indoors.
The next step in this artificial photosynthesis is to improve its efficiency and increase the purity of hydrogen. Achieving this would allow hydrogen to be fed directly into fuel cells, reducing the additional energy consumption and costs associated with traditional processes.
The Michigan researchers believe that “artificial photosynthetic devices will be more efficient than natural photosynthesis, providing a path to carbon neutrality.”