Removal of ethylene by synthesized Ag/TiO₂ photocatalyst under visible light irradiation

Photocatalysts based on titanium dioxide (TiO₂) were widely applied to solve environmental problems such as water and air pollution treatment. Currently, the application of these compounds for food packaging is increasing. This study prepared silver (Ag) doped TiO₂ photocatalyst (Ag/TiO₂) for the decomposition of gas ethylene (Eth), which is the main factor that causes fruits to over-ripen and damage or decay. It found that the doping of Ag could improve the optical property and light adsorption ability of Ag/TiO₂ photocatalyst, which directly enhanced the photocatalytic decomposition of Eth performance. Under visible light, Ag/TiO₂ could depredate 91.2% of Eth, while the removal performance by using the original TiO₂ was 43.9%. The increased initial concentration of Eth from 5 to 30 ppm could inhibit the photocatalytic efficiency of Ag/TiO₂ from 98.6 to 69.2%. Besides, the relative humidity and gas flow rate are roles in the Eth decomposition process. The recycling experiment confirmed that Ag/TiO₂ had good reusability with a slight loss in photocatalytic performance (18.6%) after ten cycles tested. The future protective application of Ag/TiO₂ for food protection during storage and transportation is discussed. This work provides a potential method to remove gas ethylene, reduce the ripening process and extend the shelf life of fruits.