Energy conversion efficiency of photoelectrochemical cells employing a titanium dioxide film anodic membrane and a hydrogen or oxygen cathode

The energy conversion efficiency at wavelengths (315-420 nm) was evaluated at 25±2° in photoelectrochem. cells, with a TiO2 film immobilized on a poly(tetraethyelene glycol diacrylate) membrane and 1N NaOH as anolyte. In one cell, Pt black in 1N H2SO4 was the counter-electrode whereas in the other cell, a Pt black cathode in 1N NaOH worked self-regeneratively. The short-circuit c.d. and open-circuit voltage were measured. The quantum efficiency was also obtained. A comparison of the exptl. values with those of conventional cells (TiO2 electrode not immobilized in a composite membrane structure) shows that no substantial difference is obsd. (outside exptl. uncertainty) in the quantum and energy conversion efficiencies and open-circuit voltages. However, the short-circuit c.d. was systematically 13-26% lower. This small effect can be attributed to a moderate increase in resistance brought about by the polymeric membrane. The performance and feasibility of photoelectrochem. membrane cells are discussed.