Enhanced photocatalytic hydrogen production from Y2O3/TiO2 nano-composites: a comparative study on hydrothermal synthesis with and without an ionic liquid

Abstract

Hetero-junction Y₂O₃/TiO₂ nano-composite (NC) photocatalysts were synthesized using a conventional hydrothermal method (Y₂O₃/TiO₂ NC_(HM)) and an ionic liquid assisted hydrothermal method (Y₂O₃/TiO₂ NC_(ILAHM)). The composite nature and physico-chemical properties of the photocatalysts prepared through both routes as a function of thermal treatment were investigated via thorough characterization. A comparison of the photocatalytic hydrogen production via water splitting is provided. It was found that the concentration of Y₂O₃ in the TiO₂ matrix and the post thermal treatment have obvious effects on the hydrogen production activity, and they were fine-tuned for enhancement of the hydrogen production. The required synergy between Y₂O₃ and TiO₂ was found to occur at an optimum concentration of 25 wt% Y₂O₃ in the TiO₂ matrix, with the sample prepared at 400 °C for 1 h. The optimized NC i.e. 25 wt% Y₂O₃/TiO₂ NC_(ILAHM) produced a promising hydrogen evolution of 1380 μmol g⁻¹ that was almost 2-fold the production from 25 wt% Y₂O₃/TiO₂ NC_(HM). The enhancement was attributed to the porous surface morphology, higher surface area and quantum yield of the NC prepared using the ionic liquid assisted hydrothermal method.