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

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.

Automated summary

In this study, a visible-light-responsive photocatalyst CuO/LNTO was synthesized by solution-based decoration of La-doped NaTaO3 crystals with CuO nanoparticles for the elimination of antibiotic contaminants. The CuO/LNTO exhibited high photooxidation activity in the photodegradation of ciprofloxacin, achieving total oxidation with good recyclability. The enhanced performance was attributed to the heterojunction formation between CuO and LNTO, improving the photoinduced charge separation and mobility for efficient pollutant removal under visible light.