Synthesis of Ti3+ self-doped SrTiO3/TiO2 hetero-photoanodes with enhanced photoelectrochemical performances under visible light

• The SrTiO3−x/TiO2−x heterojunction are synthesized using molten aluminium reduced method for the first time.
• The SrTiO3−x/TiO2−x sample exhibits remarkably enhanced absorption in visible light region.
• The Ti3+ decreases the surface recombination centers, enhances the charge separation and transport.
• The optimally Ti3+ self-doped sample yield a photocurrent density of ∼0.85 mA/cm2 at 0.6 V vs SCE under the visible light irradiation.

Herein, we demonstrate a facile and effective method for fabricating Ti3+ self-doped SrTiO3/TiO2 hetero-photoanodes to fundamentally improve the visible-light-driven photoelectrochemical (PEC) performance. Electron paramagnetic resonance (EPR) spectra confirm the presence of Ti3+ in the as-prepared samples. This modified SrTiO3−x/TiO2−x sample exhibits remarkably enhanced absorption in visible light region and efficient charge separation and transport. The optimally Ti3+ self-doped sample yield a photocurrent density of ∼0.85 mA/cm2 at 0.6 V vs SCE under the visible light irradiation, which is almost 20 times higher than pristine TiO2 at the same conditions. These findings may provide new insights for developing high performance visible light photocatalysts.