Synergistic Z-Scheme Charge Separation and PMS Activation in Engineered 2D CoTiO3/TiO2 Composites for Superior Photocatalysis

A plate-like CoTiO 3/ TiO 2 nanocomposite was synthesized via H 2 O 2 pretreatment of layered hydrogen titanate (HTO) followed by Co 2+ ion exchange and topotactic transformation. The H 2 O 2 pre-intercalation expanded the interlayer spacing and introduced active peroxy groups, facilitating subsequent ion exchange. The resulting composite retained the plate-like morphology and exhibited enhanced visible-light photocatalytic degradation of rhodamine B (RhB). Under optimal conditions, the degradation efficiency reached 96.4%. A strong synergistic effect between the catalyst and peroxymonosulfate (PMS) was observed, significantly accelerating RhB removal. The catalyst also showed good reusability (> 90% after 5 cycles). Structural, morphological, and optical characterizations (XRD, SEM, TEM, XPS, Raman, FTIR) were performed. This work provides a novel strategy for designing 2D heterojunction photocatalysts with efficient PMS activation. Highlights • A novel “H 2 O 2 pre-intercalation–topotactic transformation” strategy is pioneered for the controllable synthesis of 2D CoTiO 3 /TiO 2 heterojunctions. • A remarkable synergy between photocatalysis and PMS activation is achieved, leading to >96% degradation efficiency of RhB with excellent cycling stability (>90% after 5 runs). • The interfacial charge-transfer pathway and the dual-channel radical generation mechanism are unraveled, establishing a clear structure–activity relationship. Graphical Synthesis route (left) and Z‑scheme charge transfer mechanism with PMS activation (right) of the plate‑like CoTiO 3 /TiO 2 composite. The alternative text for this image may have been generated using AI.