Heterojunction formation between AgNbO3 and Co3O4 for full solar light utilization with improved charge-carrier separation

Abstract

In the present study, the charge-carrier recombination of visible light active perovskite silver niobate (AgNbO3) was reduced by forming heterojunction with Co3O4 through simple impregnation and calcination route. The loading percentage of Co3O4 was varied as 2, 5, and 10 wt.%. The XRD study revealed reduced interlayer spacing in the composite due to the replacement of the bigger Ag+ ions by the smaller Co2+ and Co3+ ions of Co3O4. It was observed that the light harvesting efficiency of the materials was increased with increased loading of Co3O4. The TEM and XPS analysis confirmed the presence of Ag nanoparticles over the perovskite in the composite. The electrochemical analysis revealed enhanced charge-carrier number density and increased charge-carrier lifetime in the composite as a result of the presence of both silver and cobalt ions in the lattice. Further this enhanced charge-carrier separation of the composites was established through photocatalysis of Bisphenol-A under both solar and LED light. Charge-trapping study indicated *O2− and *OH as the major radicals involved and Z-scheme as the predominant charge transfer pathway for generation of these reactive oxygen species. Graphical abstract: [Figure not available: see fulltext.]