New inexpensive materials bring cheap hydrogen fuel closer to reality
Researchers have combined cheap, oxide-based materials to split water into hydrogen and oxygen gases using solar energy with a solar-to-hydrogen conversion efficiency of 1.7 percent, the highest reported for any oxide-based photoelectrode system.
Kyoung-Shin Choi, a chemistry professor at the University of Wisconsin-Madison and postdoctoral researcher Tae Woo Kim created solar cells from bismuth vanadate using electrodeposition - the same process employed to make gold-plated jewelry or surface-coat car bodies - to boost the compound's surface area to a remarkable 32 square meters for each gram.
Choi said that without fancy equipment, high temperature or high pressure, we made a nanoporous semiconductor of very tiny particles that have a high surface area, asserting that more surface area means more contact area with water, and, therefore, more efficient water splitting.
Bismuth vanadate needs a hand in speeding the reaction that produces fuel, and that's where the paired catalysts come in.
Choi and Kim exploited a pair of cheap and somewhat flawed catalysts - iron oxide and nickel oxide - by stacking them on the bismuth vanadate to take advantage of their relative strengths.
The dual-layer catalyst design enabled simultaneous optimization of semiconductor-catalyst junction and catalyst-water junction.
She expects the basic work done to prove the efficiency enhancement by nanoporous bismuth vanadate electrode and dual catalyst layers will provide labs around the world with fodder for leaps forward.
The study has been published in the journal Science.
(Posted on 23-02-2014)