Fabrication of Dandelion-like p-p Type Heterostructure of Ag2O@CoO for Bifunctional Photoelectrocatalytic Performance.

A novel three-dimensional purple dandelion-like hierarchical Ag2O@CoO heterojunction with an appropriate redox potential was constructed by chemical precipitation of Ag2O nanoparticle on flower-like CoO. By feat of this hierarchical structure, the Ag2O@CoO photocathode showed significantly high photoelectroreduction activities toward p-nitrophenol (p-NP) and Cr(VI). The high performance of Ag2O@CoO was mainly attributed to the specific structural characteristics and synergistic effect of each chemical component. This hierarchical structure could effectively increase the specific surface area, provide more exposed active edges, and be beneficial for multiple light reflection/scattering channels and light utilization efficiency. The introduction of Ag2O optimized the composition and further improved the band structure, resulting in an improved separation of photogenerated electrons and holes. The unique photocathode achieves a removal efficiency of 86% for photoelectrocatalytic p-NP degradation after 120 min and 95% for Cr(VI) after 40 min under visible light irradiation with excellent stability. This research provided a simple way for the synthesis of photoelectrocatalytic material with potential applications in the field of environmental governance with visible light illumination.