Optimization of conditions for hydrogen production from anodized TiO2 nanotube-based photoelectrochemical cells.

The photocatalytic splitting of water into H2 and O2 using semiconductors has received much attention, especially in terms of its potential application to the direct production of H2 as a clean energy source. In this study, the H2 yield increased with increasing reactor temperature, but the TiO2 nanotube arrays collapsed after prolonged operation at temperatures over 75 degrees C. We found that aqueous Na2SO3 reagent was the best hole scavenger of the different aqueous solutions examined. Using the optimum temperatures and electrolytes, we conducted an experiment to produce H2 from solutions with different pH values, and found that acidic conditions were better in terms of the amount of H2 produced. The results obtained allowed us to identify the optimal temperature, electrolyte and pH conditions required to produce H2 by photochemically splitting water.