A novel Ag2O-TiO2-Bi2WO6/polyvinyl alcohol composite film with ethylene photocatalytic degradation performance towards banana preservation

Abstract In this research, the Ag2O-TiO2-Bi2WO6(ATB) ternary heterojunction photocatalyst was synthesized by hydrothermal and surface deposition method, and the ATB/PVA composite film with ethylene photocatalytic degradation performance was constructed by the casting method. The structure and properties of ATB and ATB/PVA films were characterized and applied to banana preservation. The results showed that the addition of ATB could improve the mechanical properties, thermal stability, oxygen and moisture resistance, and reduce the crystallinity and light transmittance of PVA films. Compared with TiO2, Bi2WO6 and TB photocatalysts, ATB had the best photocatalytic degradation effect of ethylene under LED light. Compared with blank group, the ethylene concentration decreased by 17.17%. This was mainly attributed to the formation of heterostructure among Ag2O, TiO2 and Bi2WO6, which promoted the separation and transfer of photogenerated carriers. The ATB/PVA composite coating could effectively prevent the respiration of the bananas by inhibiting gas exchange and degrading ethylene, which reduced the weight loss, inhibited glycogen decomposition, improved the pulp hardness, increased titratable acid content, reduced the PPO activity, hindered the phenol oxidation and keep better apparent color of bananas. The safety study suggested that the ATB/PVA film is safe for bananas packaging application.