Ag2O/sodium alginate-reduced graphene oxide aerogel beads for efficient visible light driven photocatalysis

Abstract In this work, one facile and green method was developed to resolve the instinct defects of pure Ag 2 O and increase visible-light photocatalytic activity of Ag 2 O-based catalyst. In which, Ag 2 O was immobilized in sodium alginate-reduced graphene oxide (ALG-rGO) aerogel beads. The as-prepared aerogel beads showed a well-defined interconnected three-dimensional porous network and displayed the highest photocatalytic activity with a mass ratio of 40:1 (ALG:rGO). For the degradation of cationic Rhodamine B (RhB) and anionic dye Orange II (OII) dyes, rate constants were 1.95 × 10 −2  min −1 and 4.13 × 10 −2  min −1 , which were 2.4 and 3.1 times higher than those of Ag 2 O/ALG aerogel beads, respectively. The further studies demonstrated that presence of rGO can effectively decrease the size of Ag 2 O, extend photoresponding range (UV to near-infrared light spectrum), speed-up separate photogenerated electrons and holes, retard charge recombination, and prolong electron lifetime and effective carrier diffusion length. The potential mechanism for RhB and OII degrading was expounded, and main active species in the degradation reactions of dyes were investigated by a series of trapping experiments. It offered a promising photocatalyst to purify the wastewater, and provided a sophisticated understanding of the pivotal role rGO acting in photocatalysis.