This image shows two electrodes connected via an external voltage source splitting water into oxygen (O2) and hydrogen (H2). The illuminated silicon electrode (left) uses light energy to assist in the water-splitting process and is protected from the surrounding electrolyte by a 2-nm film of nickel. (Illustration: Guosong Hong, Stanford University)
The chemical energetics of using sunlight to split water into hydrogen and oxygen (Image: B. Dodson)
Photoelectrochemical (PEC) cells can use sunlight to sustainably split water into hydrogen and oxygen, but efficient PEC materials tend to corrode rapidly in use. A Stanford research group has been studying this problem, and has found that depositing a thin layer of nickel atoms on a silicon PEC electrode allows it to operate for over 80 hours with no sign of corrosion.
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