Recyclable Ag@AgBr-gelatin film with superior visible-light photocatalytic activity for organic degradation

Recyclable Ag@AgBr-gelatin film was fabricated by a versatile route, i.e., embedding Ag@AgBr grains into gelatin matrix, constructing 3D network structures via the cross-linking reaction between gelatin and cross-linking agent 1,3-bis(vinylsulfonyl) propanol, and forming Ag@AgBr-gelatin film on the nylon mesh. The microstructures and chemical compositions of the obtained films were analyzed by the means of scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermo gravimetry/differential thermal analyzer, and Fourier transform infrared spectroscopy. It was revealed that the 3D network structure was formed via the cross-linking reaction between gelatin and cross-linking agent 1,3-bis(vinylsulfonyl) propanol (BVP). Photocatalytic degradation of methyl orange indicated that Ag@AgBr-gelatin film exhibited excellent visible-light photocatalytic activity and recyclability, due to the reason that the 3D networks can efficiently fix Ag@AgBr but hardly hinder the transmissions of reactants and degradation products. The adhesion fastness of Ag@AgBr-gelatin film on nylon mesh enhances with increasing the dosage of cross-linking agent BVP, and the lower limit of BVP dosage for forming unbroken film is 0.02 g/m2. Excessive cross-linking would make gelatin network structure too denser, resulting in the decline of photocatalytic activity.