Photoactivity enhancement of La-doped NaTaO3 nanocrystals by CuO decoration toward fast oxidation of ciprofloxacin under visible light

Abstract

The use of antibiotics has increased over recent years owing to the spread of infections worldwide. The spread of this toxic matter, especially in water, has become crucial to public health and the environment. Accordingly, there has been extensive research, and numerous approaches have been proposed for the eco-friendly elimination of antibiotic contaminants. In this study, we designed a solution-based synthesis of La-doped NaTaO3 crystals, which become visible-light-responsive photocatalysts upon decoration with 1.0–4.0 wt% CuO nanoparticles. CuO/LNTO exhibited a mesoporous texture and large specific surface areas in the range 199–221 m2 g−1 compared to 230 m2 g−1 for pure LNTO. Tuning the CuO content in LNTO provides a material with a broad absorbance in the visible range and a prominent attenuation of the bandgap energy from 4.05 to 2.1 eV at CuO content of 3.0 wt%. CuO/LNTO was used for the photodegradation of ciprofloxacin as a nascent antibiotic model. The 2.0 gL−1 dose of 3%-CuO/LNTO accomplished total oxidation of CPF with photoreaction rate of 0.071 min−1 in water after 60 min visible light illumination and maintained substantial recyclability of five cycles. The high photooxidation activity of CuO/LNTO is ascribed to the formation of a heterojunction between CuO and LNTO. The heterojunction improved the photoinduced charge separation and mobility, as confirmed by the photoluminescence and photocurrent studies. This novel study proposes that the decorated sol-gel produced perovskite oxide nanostructures are promising photocatalysts is for the fast elimination of antibiotic contaminants under visible light.