New Alternative Catalyst Choice Makes Hydrogen Fuel Cheaper And Sustainable

Scientists all around the world are busy trying to develop alternative, nonconventional fuel and energy sources. A general problem with a lot of these options is that the technology used for their processing and development is complex. So such fuels are eco friendly but not sustainable. Hydrogen fuel technology is one such example. But now, a group of researchers have created a substitute for the expensive platinum catalyst particles. This catalyst is cheap and abundantly available. This awesome discovery was covered in last week’s Nature Materials. This idea is the brainchild of a research team comprising intellectuals like theorist Jens Norskov of the Department of Energy's SLAC National Accelerator Laboratory and Stanford University and a team of colleagues led by Ib Chorkendorff and Soren Dahl at the Technical University of Denmark (DTU).

This novel technology has given a boost to the worldwide research going on for copying the technique by which plants create their fuel from sunlight. Hydrogen is a clean and dense fue;l that forms water as a byproduct after it burns. It doesn’t emit any carbon residue. Currently, natural gas is used for hydrogen fuel production. This results in large carbon footprints due to tremendous amount of CO2. Photo electrochemical (PEC) splitting method for producing hydrogen from sunlight and water is a better and cleaner option. When the sun rays are incident on the PEC cells, the water molecule splits into its constituents i.e. hydrogen and oxygen.

Till now, much progress was not made in this technology because of the lack of cheap catalysts that would increase the speed of liberation of oxygen and hydrogen molecules. The major research work done by the American- Danish collaboration of scientists was amalgamating theoretical expertise and advanced computation with synthesis and testing to expand the quest for identification of new catalysts. As a result, the trial and error methods are replaced by newer methods for rational design of the catalysts. This has helped to speed up the development in this field. So the team first solved the problem related to hydrogen. Scientists at the DTU created an energy harvesting device that used the power from the solar spectrum for converting single hydrogen ions into H2 gas. Generally, platinum particles are used as catalysts for this reaction. After studying the action of the catalysts and making a string of calculations, they found that molybdenum sulfide is the replacement for platinum. Molybdenum is very cheap and abundantly available in nature.

The team has also done some improvements in the machine parts by adding a "chemical solar cell" for optimizing the sunlight gathering capacity of the device. The scholars at DTU designed light absorbers made up of silicon arranged in closely packed pillars, and dotted the pillars with tiny clusters of the molybdenum sulfide. When the pillars were exposed to the sun, Hydrogen gas fizzed out as bubbles from the PEC cells. The results were even better than those obtained by using platinum catalyst.

The hydrogen gas-generating device is only part of a complete photo-electrochemical cell. The other half of the PEC would generate oxygen gas from the water; though hydrogen gas is the goal, without the sufficient generation of oxygen, the whole cell stops working. Once this problem gets solved, we can start making hydrogen just like the plants.