Bovine serum albumin assisted synthesis of Ag/Ag2O/ZnO photocatalyst with enhanced photocatalytic activity under visible light

Abstract

This work provides an environmental friendly route to fabricate ternary silver/silver oxide/zinc oxide (Ag/Ag2O/ZnO) photocatalyst with assistance of bovine serum albumin (BSA). The structural analysis indicates that Ag/Ag2O/ZnO photocatalyst is a 3D-flowerlike architecture. Nanoparticles composed of Ag and Ag2O in diameter about 40 nm attach on the surfaces of ZnO “petals” and form a heterojunction structure with ZnO. The ultraviolet-visible (UV–vis) spectra and photoluminescence (PL) spectra show that the obtained Ag/Ag2O/ZnO nanocomposite displays an enhanced visible-light absorption and a decreased fluorescence emission compared to that of ZnO. The photocatalytic performance of Ag/Ag2O/ZnO nanocomposite was evaluated by photocatalytic degradation of methylene blue (MB) under simulated visible light irradiation. The results indicate that Ag/Ag2O/ZnO nanocomposite exhibits better photocatalytic activity than that of single- and two-component photocatalysts including ZnO, Ag2O, TiO2 and Ag/ZnO. Ag/Ag2O/ZnO nanocomposite also has a good recycling stability and still maintains a high degradation efficiency (85%) after four recycles. The improved photocatalytic activity is credited to the synergistic effect of Ag, Ag2O and ZnO nanophases in the Ag/Ag2O/ZnO heterojunction, which results in an effective charge separation and a low recombination of photo-induced electron-hole pairs.