Although engineers have long known how to produce hydrogen using solar energy, a new method will make it possible to do it in a more "green" way
The article is published with the approval of Scientific American Israel and the Ort Israel network 23.07.2017
Hydrogen is currently used to upgrade heavy crude oil and produce ammonia, an essential building block for the production of essential fertilizers for modern agriculture. It can also be used as a fuel to produce green energy, and used as a component in environmentally friendly fuel cells in cars and trucks. But since hydrogen is mostly produced from natural gas heated with steam, in a process that emits greenhouse gases, other environmental problems arise. Scientists are therefore trying to develop an alternative process that would use a renewable energy source. Such a breakthrough was recently reported In the article which was published in the journal Nature Energy.
The new approach uses a photoelectrochemical device (PEC), a type of solar cell that can in principle break down water molecules more efficiently than other methods. Scientists have been trying for a long time to design a photo-electrochemical device that would not only be efficient, but also durable enough to be economically viable. Real progress happened a year and a half ago, whenJohn Turner, an electrochemist at the American National Laboratory for Renewable Energy (NREL), designed a device built from layers of two semiconductor materials: gallium indium phosphor (GaInP) and Gallium Arsenide (GaAs). Turner's facility was the world's most efficient facility for converting solar energy into hydrogen until 2015. But because the acidic solution the cell was exposed to while operating destroyed it quickly, the hydrogen it produced was too expensive.
In the new facility, which was developed by a group of researchers led by the chemist Jing Gu From San Diego State University, the team added a coating to the semiconductor layers that prevents the acid corrosion. These protective coating layers greatly extended the life of the efficient Turner-designed facility. Durability tests found that it retained 80% of the capacity of the original photoelectrochemical device. A "hydrogen economy" where consumers can generate their own hydrogen to power their cars or cool and heat their homes is not yet in the offing, but this engineering feat nonetheless makes the vision of the hydrogen economy sound a little more realistic.
