Semiconductor-septum photoelectrochemical solar cell for hydrogen production

In the present study, photo-electrochemical and hydrogen evolution characteristics of a new type of TiO2(ns) and TiO2(ns)–In2O3/Ti septum based semiconductor-septum photo-electrochemical (SC-SEP, PEC) solar cell has been studied. The SC-SEP cell in the configuration of SCE/1 M NaOH/TiO2(ns)/Ti/H2SO4+K2SO4/PtCE, PtWE showed the photo-voltage and photo-current of 0.72 V and 8.6 mA/cm2, whereas the SC-SEP cell employing In2O3 admixed TiO2(ns) photo-electrode and having the configuration: SCE/1 M NaOH/TiO2(ns)–In2O3/Ti/H2SO4+K2SO4/PtCE, PtWE, showed the photo-voltage and photo-current of 0.92 V and 14.6 mA/cm2, respectively. The hydrogen gas evolution for the SC-SEP cell based on TiO2(ns)/Ti photo-electrode was found to be 8.2 l/h m2, on the other hand the In2O3 modified TiO2(ns) exhibited a higher hydrogen gas evolution rate of 11.8 l/h m2. Evidence and arguments have been put forward to show that the presence of In2O3 over TiO2 makes the system posses the advantages of a colloidal photochemical system. The better performance of the new photo-electrode is thought to be due to improved spectral response and catalytic activity of In2O3 in regard to the hydrogen gas evolution kinetics.