Water splitting with silver chloride photoanodes and amorphous silicon solar cells.

A thin silver chloride layer deposited on a conducting support photocatalyzes the oxidation of water to O(2) in the presence of a small excess of silver ions in solution. The light sensitivity in the visible part of the spectrum is due to self-sensitization caused by reduced silver species. Anodic polarization reoxidizes the reduced silver species. To test its water splitting capability, AgCl photoanodes as well as gold colloid modified AgCl photoanodes were combined with an amorphous silicon solar cell. The AgCl layer was employed in the anodic part of a setup for photoelectrochemical water splitting consisting of two separate compartments connected through a salt bridge. A platinum electrode and an amorphous silicon solar cell were used in the cathodic part. Illumination of the AgCl photoanode and the amorphous Si solar cell led to photoelectrochemical water splitting to O(2) and H(2). For AgCl photoanodes modified with gold colloids an increased photocurrent, and consequently a higher O(2) and H(2) production, were observed.