SIGNIFICANT EFFICIENCY INCREASE IN SELF-DRIVEN PHOTOELECTROCHEMICAL CELL FOR WATER PHOTOELECTROLYSIS

In a recent theoretical paper, it has been shown that high efficiency PEC cells for water electrolysis can be formed by using protected nonoxide low bandgap semiconductors as photoanodes and suitably chosen p-type semiconductor with electrocatalysts on the surface, as photocathodes. In this paper, we report the consequences of this theoretically based conclusion on the performance of a self-driven PEC cell for water electrolysis that employs p-InP with Pt electrocatalyst as the photocathode and protected n-GaAs as a photoanode. Evaluations of the solar conversion efficiency for the production of hydrogen and electricity showed a maximum total conversion efficiency of 8. 2%, the conversion being predominantly to hydrogen.