Enhanced photocatalytic performance of intercalated 2D BiOBr nanosheets into 3D knob-like Bi2WO6 for the degradation of antibiotics and textile pollutants

Abstract

The development of efficient, stable, and scalable photocatalysts for wastewater remediation remains a critical challenge in environmental science. In this work, a novel 3D/2D Bi₂WO₆/BiOBr heterostructure was synthesized via a low-cost solvothermal-hydrothermal method. Structural and morphological analyses confirmed the successful integration of 3D knob-like Bi₂WO₆ with 2D BiOBr nanosheets, forming a robust heterojunction. UV–Vis measurements revealed a band gap of 2.6 eV for the Bi₂WO₆/BiOBr composite, positioned between the band gaps of pristine Bi₂WO₆ (2.54 eV) and BiOBr (2.82 eV), indicating a hybridized electronic structure resulting from interfacial electronic coupling and the redistribution of electronic states. Photoluminescence (PL) and valence band XPS measurements showed favorable band alignment, supporting enhanced charge separation. XPS analysis further confirmed interfacial electronic interactions through notable positive shifts in Bi 4f, W 4f, Br 3d, and O 1s binding energies. The heterostructure exhibited outstanding photocatalytic degradation efficiencies of 99.8 % for Rhodamine B in 27 min and 69.1 % for Ciprofloxacin during 30 min, outperforming the pristine materials. Scavenging tests identified OH, h⁺, and O₂⁻ as the main reactive species. The photocatalyst retained over 94 % efficiency after five cycles, with XRD confirming phase stability. These findings highlight the Bi₂WO₆/BiOBr heterostructure as a promising and recyclable photocatalyst for environmental remediation under visible light.