Structural Engineering of Au─Ag Heterometallic Nanoparticles Using Multidentate Polyoxometalate Ligands

Heterometallic nanoparticles possess immense potential in catalysis and materials science; however, achieving precise structural control remains a major challenge. In this work, we report a facile co-reduction strategy for the preparation of gold-silver (Au-Ag) heterometallic nanoparticles stabilized by multidentate polyoxometalates, which act as functional inorganic ligands. Notably, core-shell-structured Au-Ag nanoparticles are preferentially obtained even under co-reduction conditions, and selective synthesis of either random alloy or core-shell particles is readily achieved by adjusting the Au:Ag precursor ratio. Metal-polyoxometalate interactions generate precursor complexes that direct nanoparticle growth, and metal-specific affinities of polyoxometalate ligands stabilize the resulting structures. The obtained Au-Ag core-shell nanoparticles can be immobilized on carbon supports without significant structural changes and exhibit superior catalytic activity and selectivity in 4-nitrophenol hydrogenation and electrochemical CO₂ reduction, outperforming random alloy and monometallic analogues. These findings demonstrate the versatility of polyoxometalate ligands in the structural engineering of heterometallic nanoparticles, opening new directions for the design of advanced catalysts and functional nanomaterials.