Enhanced photocatalytic degradation of organic pollutants via black phosphorus-mediated electron transfer in g-C3N4/BiOI: Degradation mechanisms and biotoxicity assessment

Abstract

Photocatalysis is a promising strategy for organic pollutant removal, yet developing a capable photocatalyst remains challenging. Using black phosphorus (BP) as an electron buffer material, the ternary composite photocatalysts of xBP/g-C3N4/BiOI were prepared through a straightforward hydrothermal method. Tetracycline (TC) and Rhodamine B (RhB) removals were 100 % (120 min) and 99 % (90 min) by photocatalytic process on 2.5 %BP/g-C3N4/BiOI under xenon lamp irradiation. Photoluminescence and electrochemical measurements confirmed BP's role in reducing charge transfer barriers between g-C3N4 and BiOI, achieving effective separation of photogenerated electrons. The degradation mechanisms of TC and RhB on 2.5 %BP/g-C3N4/BiOI were revealed by the quenching experiments, electron paramagnetic resonance spectroscopy tests, three-dimensional excitation-emission matrix fluorescence spectrum, and liquid chromatography-mass spectrometry analyses. Plant toxicity assessment experiments confirmed the non-toxic nature of the TC and RhB degradation solutions. Plants grown in the treated solutions exhibited declining trends in both Malondialdehyde and Peroxidase indices compared to untreated solutions. This study offers a fresh approach to advanced photocatalyst design using charge transfer buffer materials.