Band-structure modulation of SrTiO3 by hydrogenation for enhanced photoactivity

A systematic study on the band-structure modulation of SrTiO3 (STO) by hydrogenation has been done by means of ultraviolet-visible (UV-vis) absorption, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and photoluminescence (PL). Hydrogenation of STO was performed by annealing STO in the forming gas of H-2:N-2 (5 %:95 %) at elevated temperatures (mostly at 1000 A degrees C). It is found that electron transfer to the defect states within the band gap of STO due to hydrogenation brings to STO visible absorption, decrease in intrinsic PL intensity, Fermi level shift, elimination of the EPR signals, and finally, an enhancement of photocatalytic ability.