Traditional hydrogen fuel cells and supercapacitors have two electrodes: one positive and one negative. The device developed at UCLA in California has a third electrode that acts as both a supercapacitor, which stores energy, and as a device for splitting water into hydrogen and oxygen, a process called water electrolysis. All three electrodes connect to a single solar cell that serves as the device's power source, and the electrical energy harvested by the solar cell can be stored in one of two ways: electrochemically in the supercapacitor or chemically as hydrogen.
The device could make hydrogen cars affordable for many more consumers because it produces hydrogen using nickel, iron and cobalt -- elements that are much more abundant and less expensive than the platinum and other precious metals that are currently used to produce hydrogen fuel.
"Hydrogen is a great fuel for vehicles: It is the cleanest fuel known, it's cheap and it puts no pollutants into the air -- just water," said Richard Kaner, the study's senior author and distinguished professor of chemistry and biochemistry, and of materials science and engineering at UCLA (above left). "And this could dramatically lower the cost of hydrogen cars."
"For hydrogen cars to be widely used, there remains a need for a technology that safely stores large quantities of hydrogen at normal pressure and temperature, instead of the pressurized cylinders that are currently in use," said Mir Mousavi, a co-author of the paper and a professor of chemistry at Iran's Tarbiat Modares University.The device also is a step forward because it produces hydrogen fuel in an environmentally friendly way. Currently, about 95 percent of hydrogen production worldwide comes from converting fossil fuels such as natural gas into hydrogen -- a process that releases large quantities of carbon dioxide into the air, said Maher El-Kady, a UCLA postdoctoral researcher and a co-author of the research (above right).
The researchers designed the nanoscale electrodes to