Defect tuned SnO2 nanolayer coated TiO2 1-D core-shell structure for enhanced overall solar water splitting

Abstract

The production of O 2 at TiO 2 surface during the photoelectrochemical water splitting is the bottleneck of the reaction process indicating the need for surface engineering of TiO 2 . Here, 1-D TiO 2 was coated with the defect tuned SnO 2 nanolayer (via sputtering) for enhanced solar water splitting activity. The sputtering strategy allows oxygen vacancy tuning of SnO 2 with complete coverage on TiO 2 . Importantly, the optimized SnO 2 /TiO 2 system exhibited the record photocurrent of 1.85 mA cm −2 at 1.23 V vs. RHE, incident photon to current efficiency of 95% at 350 nm, and H 2 and O 2 production with ∼90% of faradaic efficiency. Band structure analysis indicated a decrease in work function along with an upward shift of Fermi level and conduction band at the electrolyte interface after SnO 2 coating. The present study demonstrates the utilization of oxygen vacancy in SnO 2 for the surface engineered electrodes for facile O 2 production during solar water splitting.