Poly(ionic liquid)-directed ambient synthesis of snowflake-like AuPd nanoparticles for selective hydrogenation catalysis

A simple, one-step, room-temperature, aqueous-phase strategy is presented for synthesizing hierarchical bimetallic nanostructures with superior catalytic properties. This approach utilizes a poly(ionic liquid) (PIL), specifically poly(1-vinyl-3-ethylimidazolium bromide) (PVEIB), which functions as an all-in-one reaction medium and structure-directing agent in aqueous solution at ambient temperature, enabling the facile preparation of well-defined AuPd nanosnowflakes (NSFs). The resulting morphology exhibits a unique four-level hierarchy assembled from nanoparticle building blocks. Systematic investigation identifies both PVEIB concentration and Au/Pd precursor ratio as critical parameters governing this hierarchical growth. Benefiting from its open architecture and the synergistic electronic interaction between Au and Pd, AuPd NSFs-1 delivers exceptional performance: it achieves high activity and selectivity (100% conversion, 100% selectivity) in the selective hydrogenation of p -nitrostyrene to p -nitrophenylethane, and maintains robust stability over five catalytic cycles. This PIL-mediated aqueous synthesis thus provides a versatile and sustainable platform for the design of advanced multimetallic nanomaterials for catalytic and related applications.