Innovative synthesis of Sb8O11Cl2·6H2O/g-C3N4 heterojunction composites via hydrolysis of Cs3Sb2Cl9 perovskite: A novel and effective photocatalyst for solar-driven wastewater treatment

In recent years, considerable attention has been directed towards the advancement of innovative composites for the remediation of environmental pollutants. This research initially corroborates the conversion of Cs₃Sb₂Cl₉ perovskite to Sb₈O₁₁Cl₂·6H₂O through hydrolysis reactions upon contact with water. Consequently, novel Sb₈O₁₁Cl₂·6H₂O/g-C₃N₄ (SOC.H/g-CN) composites are synthesized by groundbreaking exploitation of a straightforward hydrolysis of Cs₃Sb₂Cl₉ within aqueous medium, incorporating g-C₃N₄ nanoparticles. A comparative assessment of the photocatalytic performance of these samples in degrading of methyl orange (MO) and tetracycline (TC) reveals an exceptional enhancement in photocatalytic efficiency of the SOC.H/g-CN composites as opposed to the pure photocatalysts. After 100 min of exposure to simulated sunlight, the SOC.H/g-CN-20 composite achieves an impressive degradation rate of approximately 98.4 % (k = 0.0522 min⁻¹) and 93.6 % (k = 0.0261 min⁻¹) for MO and TC, respectively. Moreover, the optimized composite’s photocatalytic effectiveness is further corroborated through degradation studies of Rhodamine B (RhB) and 4-nitrophenol (4-NP), yielding rates of 99.6 and 71.2 %, respectively. The superior photocatalytic efficacy of this composite is ascribed to enhanced photoharvesting abilities, improved charge carrier separation, and a decreased recombination rate of photoinduced charge pairs resulting from the building of a type-II heterojunction between Sb₈O₁₁Cl₂·6H₂O and g-C₃N₄. Additionally, radical-trapping experiments underscore the main role of ^•O₂⁻ radicals in the photocatalytic reactions. The SOC.H/g-CN-20 composite also demonstrates notable operational stability, retaining over 96 % of its photocatalytic efficiency following five sequential cycles. Altogether, this study introduces a pioneering approach for the development of composite solar-driven photocatalysts effective in the elimination of wastewater pollutants.