Synthesis of bimetallic-nanocrystal-decorated rice bowl-shaped polymer particles for catalytic Cr(VI) remediation

Abstract

Rice-bowl shaped polymer particles with convex and concave surfaces have emerged as promising noble metal catalyst supports. However, their synthesis and integration with catalytic materials using environmentally friendly methods have remained a challenge. This study presents a sustainable and efficient approach for synthesizing rice-bowl-shaped polystyrene (PS) particles and explores their potential as catalyst supports. The key to achieving this morphology lies in the utilization of anisotropic PS seeds, specifically hollow dimpled PS seeds. Uniform rice-bowl-shaped PS particles are obtained by dispersing these seeds in an oil-in-water (O/W) emulsion and allowing them to dry under ambient conditions. Non-toxic reducing agents and environmentally friendly solvents are employed for the in-situ chemical reduction process and galvanic displacement reaction to synthesize bimetallic (Ag/Pd) nanocrystals on the surfaces of the PS particles. The resulting Ag/Pd-coated PS particles exhibit excellent catalytic activity as microreactors for Cr(VI) reduction in water, while demonstrating remarkable stability during repeated use without significant loss of activity. Furthermore, the shape of the rice-bowl particles facilitates efficient packing and stacking, leading to enhanced catalytic performance not only in bulk solutions but also in confined spaces. This study highlights the potential of rice-bowl-shaped polymer particles as efficient and environmentally friendly catalyst supports, paving the way for the development of green catalytic applications.