Low temperature electrodeposition of SiOx films photoactive in water solution

We report a low temperature, an electrochemical way of preparation of a photoanode made of n-type silicon oxide based films, at which surface photoelectrochemical oxygen evolution was observed with no need to deposit of other materials. Conditions of electrosynthesis, under which the electrochemical reduction of silicon chlorides in non aqueous solutions leads to silicone oxide based films are described. The photoactivity of prepared photo-anodes was reproducible and the observed photocurrent sustained for many hours. The most stable photocurrent was observed for films deposited at −2.7 V. Water oxidation was observed while occurring at the onset potentials smaller than 0.2 V comparing to the dark water splitting potential. The highest photocurrent was observed at −0.3 V (thermodynamic value 1.02 V vs. Ag wire), which means energy saving corresponding to ca. 1.3 V. The results demonstrate that a low temperature electrodeposition of silicon oxide based films can be an alternative route for fabrication of photoanode for water photosplitting devices.