Abstract

Ion intercalation is a promising approach for improving the activity of 2D photocatalysts by modulating their electronic structure and charge separation. However, traditional intercalation routes including ion exchange still suffers from low interaction and slow charge transfer, etc. Herein, a pre-adsorption followed by in-situ structural transformation strategy is developed in the example of Ca²⁺-intercalated Bi₂O₂CO₃ from the precursor of Ca²⁺-adsorbed BiOCl. Meanwhile, the concept of “electron-donation-ion-intercalation” is proposed. The electron-donating ability of Ca species not only induces significant charge redistribution toward O atoms, increasing the electron density around oxygen sites and elevating the energy state of O 2p orbitals, thereby effectively narrowing the bandgap from 3.10 eV in pristine Bi₂O₂CO₃ to 2.25 eV, but also modifies the charge transfer pathway, enabling ultra-fast and efficient separation of photogenerated carriers. This also promotes the participation of charge carriers in surface reactions, rather than their localization within intrinsic defects. Consequently, the first-order kinetic constant for the degradation of RhB under visible light irradiation is enhanced by 17.33 times over optimized BiOC-Ca-3 compared to the pristine sample. This work offers an in-situ transformation approach for constructing ion-intercalated 2D materials and gives a novel insight into the enhanced photocatalytic activity of cation-intercalated catalysts.