Highly efficient CoTiO3/MOF-derived In2S3 photo-electrocatalysts: Degradation kinetics, pathways, and mechanism

MOF-derived catalysts with well-defined morphology have garnered significant interest and research in their potential applications in the fields of photocatalysis and electrocatalysis. In the article, a neoteric and promising photocatalytic system of CoTiO3/MOF-derived In2S3 type-Ⅱ heterogeneous catalyst with different weight percentages was prepared by a simple hydrothermal method. The system displayed remarkable photocatalytic and electrocatalytic properties. Under optimal conditions, the CoTiO3/MOF-derived In2S3 catalyst achieved a high photocatalytic degradation efficiency within 30 min for terramycin, tetracycline hydrochloride (TCH), Rhodamine B (RhB), methylene blue (MB), bright blue (BB) and methyl orange (MO). The respective degradation efficiencies were 91.07%, 87.77%, 99.85%, 99.78%, 97.85%, and 93.94%. In addition, when subjected to H2 evolution reaction (HER) at a current density of 10 mA/cm2, CoTiO3/MOF-derived In2S3 (65 mV) demonstrated superior electrocatalytic performance compared to pure CoTiO3 (429 mV) and MOF-derived In2S3 (109 mV). Surprisingly, cyclic voltammetry yielded an electrochemical active area of 62 cm2, further confirming the enhanced electrochemical performance of CoTiO3/MOF-derived In2S3. The results of the characterization indicate that design of type-Ⅱ heterostructure significantly enhances the specific surface area and interfacial charge transfer. In addition, the results of liquid chromatography-mass spectrometry (LC-MS) revealed the degradation intermediates of RhB and suggested its possible degradation pathways. This lays a solid foundation for the development of catalysts which are viable for use in both photocatalysis and electrocatalysis.