Z-scheme 0D/3D p-Ag₆Si₂O₇ nanoparticles-decorated n-Bi₂O₂CO₃ micro-flowers heterojunction photocatalyst for efficient degradation of organic contaminants

Novel Z-scheme 0D/3D p-Ag₆Si₂O₇/n-Bi₂O₂CO₃ micro-flowers heterojunctions were fabricated by a CTAB-aided deposition and in-situ growth route for the first time. The photocatalysts were characterized systematically via XRD, XPS, SEM, BET, EDS, TEM and Mott-Schottky. Under simulated sunlight irradiation, the AB_0.15 (the molar ratio of Ag₆Si₂O₇/Bi₂O₂CO₃ is 0.15:1) presented optimal removal rate of methyl orange (0.1064 min⁻¹), which was 18 and 15 times that of Bi₂O₂CO₃ and Ag₆Si₂O₇, respectively. Simultaneously, the AB_0.15 can effectively eliminate colourless ciprofloxacin from water (0.0768 min⁻¹), which ruled out the photosensitization. The outstanding organics mineralization ability and photocatalytic stability of AB_0.15 were verified by TOC and cyclic tests. As evidenced by UV–vis DRS, PL and electrochemical experiments, AB_0.15 exhibited broaden light absorption and improved charge separation efficiency compared with single-phase samples. Trapping experiments and ESR electron spin test proved that h⁺ and •O₂⁻ were principal active species during the degradation. The performance enhancement was mainly ascribed to the synergistic action of p-n heterojunction built-in electric field and Z-scheme charge migration mode, extremely promoted the activization and separation of carriers. This study offers a new perspective for designing high-performance Z-scheme photocatalysts for sewage purification.