Hydrogen on Demand Research Breakthrough

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Technion-Israel Institute of Technology researchers have developed a new approach to the production of hydrogen from water using solar energy. In findings published today in Nature Materials, the researchers explain that this approach will make it possible to produce hydrogen in a centralized manner at the point of sale (for example, at a gas station for electric cars fueled by hydrogen) located far from the solar farm. The new technology is expected to significantly reduce the cost of producing the hydrogen and shipping it to the customer.

The study was led by Avigail Landman, a doctoral student in the Nancy & Stephen Grand Technion Energy Program (GTEP), and Dr. Hen Dotan from the Electrochemical Materials & Devices Lab. Ms. Landman is working on her doctorate under the guidance of Prof. Avner Rothschild from the Faculty of Materials Science and Engineering, and Prof. Gideon Grader, Dean of the Faculty of Chemical Engineering.

Hydrogen is considered one of the most promising energy carriers for vehicles and various other uses because of its salient advantages:
1. Hydrogen can be produced from water, and therefore production does not depend on access to non-renewable natural resources.
2. Using hydrogen fuel would reduce the dependence on fossil fuels such as oil and natural gas, whose availability depends on geographical, political and other factors, and would increase the energy available to the earth’s population.
3. Unlike diesel and gasoline engines that emit considerable pollution into the air, the only byproduct of hydrogen fuel utilization is water.

The first diagram shows a conventional PEC device, with a membrane separating the two products (oxygen on the right, hydrogen on the left).

Because of the advantages of hydrogen fuel, many countries – led by Japan, Germany and the United States – are investing vast sums of money in programs for the development of environmentally friendly (“green”) technologies for the production of hydrogen. Most hydrogen is currently produced from natural gas in a process that emits carbon dioxide into the air, but it is also possible to produce hydrogen from water by splitting the water molecules into hydrogen and oxygen in a process called electrolysis.

 However, since electricity production itself is an expensive and polluting process, researchers at the Technion and around the world are developing a photoelectrochemical (PEC) cell that utilizes solar energy to split water into hydrogen and oxygen directly, without the need for external power source.

The main challenges in the development of PEC solar farms for the production of hydrogen are 1.) keeping the hydrogen and the oxygen separate from each other, 2.) collecting the hydrogen from millions of PEC cells, and 3.) transporting the hydrogen to the point of sale. The Technion team solved these challenges by developing a new method for PEC water splitting. With this method, the hydrogen and oxygen are formed in two separate cells – one that produces hydrogen, and another that produces oxygen. This is in contrast to the conventional method, in which the hydrogen and oxygen are produced within the same cell, and separated by a thin membrane that prevents them from intermixing and forming a flammable and explosive mixture.

The new process allows geographic separation between the solar farm consisting of millions of PEC cells that produce oxygen exclusively, and the site where the hydrogen is produced in a centralized, cost-effective and efficient manner. They accomplished this with a pair of auxiliary electrodes made of nickel hydroxide, an inexpensive material used in rechargeable batteries, and a metal wire connecting them.