Optimization of conditions for hydrogen production from anodized TiO ₂ nanotube-based photoelectrochemical cells

The photocatalytic splitting of water into H ₂ and O ₂ using semiconductors has received much attention, especially in terms of its potential application to the direct production of H ₂ as a clean energy source. In this study, the H ₂ yield increased with increasing reactor temperature, but the TiO ₂ nanotube arrays collapsed after prolonged operation at temperatures over 75 °C. We found that aqueous Na ₂SO ₃ reagent was the best hole scavenger of the different aqueous solutions examined. Using the optimum temperatures and electrolytes, we conducted an experiment to produce H ₂ from solutions with different pH values, and found that acidic conditions were better in terms of the amount of H ₂ produced. The results obtained allowed us to identify the optimal temperature, electrolyte and pH conditions required to produce H ₂ by photochemically splitting water.