A New Class of Molecular-Based Photoelectrochemical Cell for Solar Hydrogen Production Consisting of Two Mesoporous TiO₂ Electrodes

A new class of molecular-based photoelectrochemical cell for solar hydrogen production consisting of a TiO₂-based photoanode modified with a polypyridyl ruthenium photosensitizer (Ru-qpy) and a TiO₂-based cathode modified with a platinum porphyrin H₂ evolution catalyst has been investigated, showing that the electron accumulation at the conduction band of TiO₂ at the photoanode is promoted via electron injection from the Ru-qpy together with hole scavenging by a sacrificial donor. Our study here for the first time unveils that the upward shift given in the Fermi level of the TiO₂ at the photoanode provides an electromotive force required to flow electrical current leading to solar hydrogen production from water even without applying external electrical bias.