In2S3‐BaTiO3 S‐Type Heterojunction Photocatalyst for Efficient Antibiotic Degradation and Hydrogen Generation

Abstract Quinolone antibiotics, particularly moxifloxacin (MOX), are increasingly contaminating aquatic ecosystems, posing significant threats to both the environment and human health. Due to its hydrophilicity and stability, traditional water treatment methods are ineffective in degrading MOX. In this study, a novel S‐type heterojunction photocatalyst, In‐Ba‐10, is introduced which combines barium titanate (BaTiO 3 ) and indium sulfide (In 2 S 3 ) to address this challenge. The In‐Ba‐10 catalyst demonstrates excellent photocatalytic performance, with a hydrogen production rate of 2050 µmol g −1 h −1 and a MOX degradation rate constant (k) of 0.049 min −1 . Compared to BaTiO 3 alone, the performance is enhanced by 48‐ and 49‐fold, respectively. Comprehensive characterization, including Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and electron microscopy, reveals that the S‐type heterojunction effectively promotes charge separation and transfer, reduces electron–hole recombination, and improves catalytic efficiency. First‐principles calculations further confirm the role of In 2 S 3 as the reduction site and BaTiO 3 as the oxidation site. In addition to its high activity, In 2 S 3 ‐BaTiO 3 shows stability over multiple cycles, making it a promising candidate for sustainable wastewater treatment. This study highlights the potential of S‐type heterojunction photocatalysts for sustainable environmental remediation and energy applications.