We know that Elon Musk refers to fuel cell cars as “fool cells.” We also know that there are people who still cling to the idea of a civilization that runs on clean hydrogen fuel. Honda and Toyota are both investing billions of dollars to bring hydrogen fuel cell cars to market. Mercedes and BMW are also experimenting with hydrogen powered cars.
Hydrogen is the most abundant element in the universe. Water is composed of two hydrogen atoms and one oxygen atom. There is an awful lot of water in the world. Why don’t we just split water molecules apart and get the hydrogen that way? There are two problems with that idea.
First, splitting water into its component atoms requires more energy than is contained in the hydrogen produced. Some people think this objection can be overcome by using solar power. That may be possible 50 years from now, but today, there is not enough solar power available to meet all of the world’s needs. There’s simply not enough left over to divert some of it to producing hydrogen. It hardly makes sense to use fossil fuels to produce hydrogen.
Second, the infrastructure to support hydrogen fueled cars is in its infancy. While a Tesla SuperCharger station might cost a few hundred thousand dollars to construct, hydrogen refueling stations can cost up to $2,000,000 or more. Once again, the future simply isn’t here yet.
Now, researchers at the Israel Institute of Technology in Israel say they have found a way to complete on part of the process required to obtain hydrogen from water with 100 percent efficiency. In other words, all the energy going into the reaction comes out the other side. That first step is known as reduction. if the second step in the process — oxidation — can be improved upon, hydrogen fuel could become a viable, emissions free fuel.
“I strongly believe that the search for clean and renewable energy sources is crucial,” lead researcher Lilac Amirav from the told Phys.org. “With the looming energy crisis on one hand, and environmental aspects, mainly global warming, on the other, I think this is our duty to try and amend the problem for the next generation.”
The process is so efficient because it was powered entirely by light. Nanorods just 50 nanometers long absorb photons from a light source and then release electrons to help split water into hydrogen and oxygen. “Our work shows that it is possible to obtain a perfect 100 percent photon-to-hydrogen production efficiency, under visible light illumination, for the photocatalytic water splitting reduction half-reaction,” said Amirav. “These results shatter the previous benchmarks for all systems, and leave little to no room for improvement for this particular half-reaction, The potential here is real.”
The key to success was identifying a bottleneck in the process. The researchers discovered that every time an electron left the catalyst, it left a vacant hole which then needed to be removed in order to continue on with the process. By redesigning the nanorods to streamline this process, the researchers increased the efficiency from 58.5 percent to 100 percent.
The team is now working on making the system more scalable. Right now, it requires a very high pH level, which isn’t ideal for real-world applications, and the nanorods can also become corroded over time. The hope is that by perfecting this half-reaction, it will move hydrogen one step closer to being a viable fuel source. “We hope to implement our design rules, experience and accumulated insights for the construction of a system capable of overall water splitting and genuine solar-to-fuel energy conversion,” said Amirav. “I believe this is an important milestone.”
Discoveries in the laboratory can take years or even decades to become commercially viable. It’s unlike that hydrogen fueling stations will start dotting the landscape any time soon. But just a few years ago, we laughed at the idea of using laptop batteries to power electric automobiles. Perhaps it would be best to keep an open mind on the subject of a hydrogen economy.
Photo credit: Phys.org