Diverse Cation Exchange in Layered Titanate Nanostructures for Tailored Catalysis

Layered titanates (LTs) offer exceptional structural and chemical tunability, enabling precise modulation of their electronic states and catalytic properties. However, systematic studies on the range of cations that can serve as intercalants for LTs remain limited, and conventional synthesis methods often require additional treatments for cation intercaltion. In this study, we present a cation-free H⁺ (H₃O⁺)-intercalated LT as a versatile platform for direct cation insertion. This LT can be intercalated with single metal cations (42 metals from five groups) or a combination of 5-30 cations without structural deformation. Intercalation with alkali metals (AMs) precisely tuned the charge density of Rh species when the prepared LTs are used as catalytic supports. Among the Rh-loaded AM-bearing LTs, Rh/K-LT delivered the highest turnover frequency (23 685 h^-1), surpassing those of other AM-intercalated systems and previously reported Rh-based heterogeneous catalysts, during propylene hydroformylation. Combined in situ/ex situ analyses and density functional theory calculations revealed that AM intercalation promotes charge transfer to Rh, thereby enhancing adsorption behavior and catalytic activity. This work establishes not only a broad cation intercalation library but also a generalizable strategy for cation engineering in LTs, highlighting the potential of intercalation-driven charge modulation for rational catalyst design across diverse reactions.