Anion-Exchange-Controlled Symmetry-Breaking-Induced Preparation of Highly Efficient Ag@AgCl x Br1 – x Photocatalysts for Sunlight

Abstract

Introducing precise shape control in nanomaterial design while maintaining the catalytic applicability of the material and keeping the whole process a sustainable one is one of the many great challenges faced by material chemists. Herein, we report one-pot synthesis of highly efficient ternary mixed halide-based silver–silver chlorobromide (Ag@AgClxBr1–x) photocatalysts, prepared via anion exchange by a slow diffusion method in aqueous medium, followed by white light-induced symmetry breaking and in situ growth of the Ag phase onto the AgClxBr1–x lattice. The precise control on the morphology is driven by the templating effect of the mixed surfactant vesicles of two cationic surface-active agents, governed by metal–surfactant interactions at the interface of vesicular domains. The ternary mixed halide structure and controlled impregnation of plasmonic Ag nanoparticles render the material highly photocatalytically efficient in broad-spectrum sunlight-driven photo-oxidation of harmful organic dyes, Rhodamine B and Methyl Orange. The photocatalyst has shown complete degradation of the dye molecules within just 15 min of sunlight irradiation, exhibiting significantly higher catalytic rates (k = 0.64 min–1) than reported for the conventional Ag@AgX nanocomposites. The reduced number of reagents in an aqueous medium, along with the usage of more economical sources of light energy for the preparation and catalytic application of the anisotropic Ag@AgClxBr1–x nanoparticles in water remediation, makes the process sustainable. The present study is expected to pave the way for the development of more strategies to design anisotropic and shape-controlled ternary mixed silver halide-based nanomaterials for their unique physicochemical properties and high potency in photosensitive applications.