Band bending and valence band shifting of sub-monolayer TiO2 functionalized SnO2 nanowires

Sub-monolayer TiO 2 over-layers were deposited on SnO 2 nanowires (NWs) by atomic layer deposition. X-ray photoelectron spectroscopy, Mott–Schottky plots and photoluminance spectra were used to investigate the band structure and the separation of electron–hole pairs at the SnO 2 /TiO 2 interface. The results showed that the valence band maximum of SnO 2 NWs shifted to lower binding energies after functionalization, and significant upward band edge bending at the interface was confirmed. The rearrangement of energy band accelerated the separation of photo-generated electron–hole pairs leading to the improvement of photocatalytic degradation rate of methyl orange (MO, C 14 H 14 N 3 NaO 3 S) under UV irradiation.