Self-floating Bi4O5Br2/P-doped C3N4/carbon fiber cloth with S-scheme heterostructure for boosted photocatalytic removal of emerging organic contaminants

Abstract

The industrial implementation of Solar-driven photocatalysis is hampered by inefficient charge separation, poor reusability and hard retrieval of powdery catalysts. To conquer these drawbacks, a self- floating S-scheme Bi₄O₅Br₂/P-doped C₃N₄/carbon fiber cloth (BB/PN/CC) composed of carbon fibers (CC) as the core and Bi₄O₅Br₂/P-doped C₃N₄ (BB/PN) nanosheets as the shell was constructed as a competent, recyclable cloth-shaped photocatalyst for safe and efficient degradation of aquacultural antibiotics. The BB/PN/CC fabric achieves an exceptional tetracycline degradation rate constant of 0.0118 min^‒1, surpassing CN/CC (0.0015 min^‒1), BB/CC (0.0066 min^‒1) and PN/CC (0.0023 min^‒1) by 6.9, 0.8 and 4.1 folds, respectively. Beyond its catalytic prowess, the photocatalyst’s practical superiority is evident in its effortless recovery and environmental adaptability. The superior catalytic effectiveness stems from the S-scheme configuration, which retains the maximum redox capacities of the constituent BB and PN while enabling efficient spatial detachment of photo-carriers. X-ray photoelectron spectroscopy (XPS), in-situ XPS, and electron paramagnetic resonance analyses corroborate the S-scheme mechanism, revealing electron accumulation on PN and hole retention on BB under illumination. Density functional theory calculations further confirm S-scheme interfacial charge redistribution and internal electric field formation. This study advances the design of macroscopic S-scheme heterojunction photocatalysts for sustainable water purification.