Photocatalytic degradation of ethylene by Ga₂O₃ polymorphs

In this work, we fabricated four different Ga₂O₃ polymorphs, namely, α-, β-, γ-, δ-Ga₂O_3, and investigated their photocatalytic activities by the degradation of ethylene under ultraviolet (UV) light irradiation. Owing to the more positive valence band, all these Ga₂O₃ polymorphs are more photocatalytic reactive than P25 during the degradation of ethylene. The normalized photocatalytic ethylene degradation rate constants of the as-prepared Ga₂O₃ polymorphs follow the order: α-Ga₂O₃ > β-Ga₂O₃ > γ-Ga₂O₃ > δ-Ga₂O₃, which is mainly determined by the position of VBM and the crystallinity of the samples. Among these Ga₂O₃ polymorphs, γ-Ga₂O₃, with the highest surface area, exhibits the highest activity during photocatalytic ethylene degradation, and the degradation rate constant is almost 10 times as that of P25. Furthermore, with the most positive CBM, γ-Ga₂O₃ produces the least CO. These attributes are beneficial for ethylene degradation during post-harvest storage of fruits and vegetables, which makes γ-Ga₂O₃ a potential candidate for practical photocatalytic ethylene degradations.