Facile Electrostatic Assembly of Core‐Dual‐Shell Cs ₂ AgBiBr ₆ ‐Based Perovskites for Photothermal‐Enhanced Photocatalysis

ABSTRACT

Lead‐free double perovskites are emerging as promising photocatalysts for environmental remediation owing to their appropriate bandgap structure and excellent light‐harvesting ability. However, their inherent photocatalytic activity remains limited, and the complex, energy‐intensive fabrication of conventional perovskite catalysts greatly impedes their scalable application. In this study, a facile and energy‐efficient electrostatic self‐assembly strategy is developed to rationally construct a core‐dual‐shell Cs ₂ AgBiBr ₆ @g‐C ₃ N ₄ @BiOBr ternary photocatalyst for organic pollutant degradation. Such a design enables strong interfacial coupling and uniform elemental distribution. The g‐C ₃ N ₄ @BiOBr dual‐shell design establishes a dual S‐scheme charge‐transfer pathway, elevating the specific surface area to 4.54 m ² /g and further optimizes the intrinsic photocatalytic performance of Cs ₂ AgBiBr ₆ . This integrated system exhibits superior light absorption, photothermal conversion behavior, and charge‐carrier dynamics. Consequently, Cs ₂ AgBiBr ₆ @g‐C ₃ N ₄ @BiOBr exhibits an organic pollutant degradation rate of 2.66 mg L ⁻¹  min ⁻¹ with a removal efficiency of 96% within 20 min. This work provides a novel and scalable route for the energy‐efficient synthesis of high‐performance photocatalysts, offering experimental support for the remediation of organic pollutants.