Photocatalytic performance of combustion-synthesized β and γ-Ga₂O₃ in the degradation of 1,4-dioxane in aqueous solution

Abstract

Nanostructures of β and γ-Ga₂O₃ were prepared by the solution combustion route using urea as fuel. The synthesized nano photocatalysts were characterized by use of XRD, FT-IR, BET, TEM, TGA–DTA, DRS, and Raman spectroscopy. XRD and TEM investigations confirmed the nanostructures; particle size was in the range 3–5 nm for γ-Ga₂O₃ and 40–50 nm for β-Ga₂O₃. The specific surface area of γ-Ga₂O₃ was 91 m² g⁻¹ and that of β-Ga₂O₃ was 24.3 m² g⁻¹. The polymorphs of gallium oxide were used as photocatalysts for decomposition of 1,000 mg/l 1,4-dioxane. More than 90 % of the 1,4-dioxane could be degraded in less than 180 min by use of 10 mg/l photocatalyst + 0.5 ml H₂O₂. The efficiency of photocatalytic degradation of 1,4-dioxane by the synthesized photocatalysts was compared with that of P-25 TiO₂ and followed the order γ-Ga₂O₃ ≥ β-Ga₂O₃ > P-25 TiO₂. The degradation was found to follow pseudo first-order kinetics.