Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

Nonstoichiometric mixed phased titania nanocomposites (TiO2−x) were deposited by reactive direct current magnetron sputtering. The authors explored the role of nonstoichiometry (as defined by oxygen deficiency in synthesis) in mixed phase titania thin films and its effects on the photoresponse and photocatalytic performance for CO2 reduction to methane under UV and visible light. Oxygen partial pressure was varied during film deposition, yielding different levels of oxygen deficiency in the films. Optimized nonstoichiometric films showed a strong redshift. The authors have identified an optimum set of synthesis conditions for TiO2−x films that produce a relative maximum in photocatalytically produced methane under both UV and visible light.