Facile synthesis of recyclable Co3O4/Co(OH)2/RGO ternary heterostructures with synergistic effect for photocatalysis

Abstract

A simple one-pot hydrothermal approach has been provided for the synthesis of a magnetically recyclable Co3O4/Co(OH)2/RGO ternary visible-light photocatalyst. The chemical reduction of graphene oxide (GO) and the formation of Co3O4 and Co(OH)2 nanoparticles occurred simultaneously during the hydrothermal reaction, and an intimate interface is built successfully between Co(OH)2 and Co3O4 nanoparticles at the nanoscale. The formation mechanism of Co3O4/Co(OH)2/RGO is investigated by means of TEM and XRD, indicating that the RGO nanosheets play a vital role in forming the ternary heterostructures. The synergistic effect between Co3O4, Co(OH)2, and RGO leads to decreased aggregation of nanoparticles, more surface active sites, two electron-transfer paths, and excellent charge transfer. As a result, a highly efficient and stable photocatalytic activity is obtained for the 6-wt% Co3O4/Co(OH)2/RGO ternary heterojunction photocatalyst under visible-light illumination (λ > 420 nm). Furthermore, the photocatalyst can be rapidly collected from the suspension using a powerful magnet and recycled with good stability, which is very meaningful in the practical industry and life.