Layered Intergrowths with SrBi₃O₄Cl₃ and Bi₂GdO₄Cl as Building Blocks Towards Stable Visible Light Mediated Photocatalysis.

Photocatalysts capable of visible light absorption that are also durable against photocorrosion are crucial to achieving overall water splitting. A unique layered intergrowth comprised of SrBi₃O₄Cl₃ and Bi₂GdO₄Cl building blocks is achieved by a flux-based approach. The feasibility of tuning the intergrowth’s optoelectronic properties was investigated by varying the stoichiometry of the intergrowths. Intergrowth formation resulted in the destabilization of the O-2p and Cl-3p orbitals, elevating the valence band maximum position. In addition, local symmetry changes around the Bi sites due to the presence of Sr²⁺ and Gd³⁺ cations play an important role in lowering the conduction band minimum position. Furthermore, the minimal recombination of photogenerated charge carriers can be attributed to the charge separation due to the presence of an internal static electric field between the layers. The systematic study of these materials conducted using X-ray diffraction and electron microscopy provides insights into how intergrowth stoichiometry serves as a lever to optoelectronic properties and photocatalytic performance of visible-light responsive multi-metal oxyhalide intergrowths.