Theory-guided doping of LaCoO3 nanoparticles for enhanced antimicrobial performance

Perovskite-type lanthanum cobaltate (LaCoO3) has been attracting extensive attention in photocatalysis; yet the performance is generally limited by the low structural defects and poor oxygen migration. Herein, results from first principles calculations show that Al and Ce codoping at the A and B sites of LaCoO3 can induce the formation of oxygen vacancies, which, along with the exposed Co (0 1 2) facets, facilitate the adsorption of oxygen and water molecules, a critical step in the photocatalytic production of reactive oxygen species that are known as potent antimicrobial agents. Motivated by these theoretical insights, Ce and Al codoped LaCoO3 is prepared experimentally via a simple sol–gel procedure. Spectroscopic measurements show that the cationic doping leads to the generation of abundant oxygen vacancies and Ce4+/Ce3+ species, fast electron transport, as well as a reduced band gap, as compared to the undoped counterpart. These unique structural characteristics enhance the separation and transport of photogenerated carriers and hence the generation of reactive oxygen species. Indeed, the obtained La0.9Ce0.1Co0.9Al0.1O3 exhibits excellent photocatalytic antibacterial activity, where 98.8% of Escherichia coli is eliminated with La0.9Ce0.1Co0.9Al0.1O3 at 1 mg mL−1 under visible photoirradiation for 30 min, in comparison to only 46.8% with undoped LaCoO3. These results underline the significance of structural engineering in enhancing the photocatalytic activity of perovskite materials for antibacterial applications.