The combination of n-type TiO2 and p-type BiOCl photooxidizing water and photoreducing the formed O2 back to water, respectively, in acidic solution enabled a sustainable photofuel cell utilizing natural light.

A photofuel cell comprising two photocatalysts TiO2 and Ag-TiO2 is demonstrated. The open circuit voltage, short circuit current, and maximum electric power of the PFC were 1.59 V, 74 μA, and 14 μW, respectively. The electron flow was rectified due to the Schottky barrier between TiO2 and Ag nanoparticles.