Impact of oxygen vacancy density in modified cobalt oxide nanoparticles on the efficiency of visible-light photocatalysis

Abstract

This study demonstrates enhanced photocatalysis on cobalt oxide nanoparticles (CoO NPs) by increasing the surface density of oxygen vacancies (V<inf>o</inf>s), achieved through base treatment and subsequent Li ion deposition. Surface Li-ion-doped CoO NPs exhibited significantly improved biomass oxidation capabilities. Li doping effectively scavenged oxygen from CoO NPs, resulting in a substantial increase in V<inf>o</inf>s and modifications to the surface structure. The induced surface defects, combined with energy engineering, enhanced the photocatalytic oxidation of biomolecules, such as 2,5-hydroxymethylfurfural. This study serves as a proof of concept, highlighting the potential of purpose-driven and mechanism-specific surface modification and defect engineering techniques, while emphasizing the need for their development and appropriate application. © 2025 Elsevier B.V., All rights reserved.