PtPd‐decorated Multibranched Au@Ag Nanocrystal Heterostructures for Enhanced Hydrogen Evolution Reaction Performance in Visible to Near Infrared Light

Abstract PtPd‐decorated multibranched Au@Ag nanocrystals (NCs) were synthesized to form heterostructures with enhanced electrochemical performance for water splitting in the visible/near infrared (vis‐NIR) light region. Three kinds of heterostructures including PtPd‐covered, PtPd‐edged, and PtPd‐tipped Multi‐branched Au@Ag NCs were fabricated by controlling the growth process of PtPd alloy nanoparticles on Au@Ag NCs. PtPd‐covered Multi‐branched Au@Ag nanocrystal exhibited the best photo‐assisted electrocatalytic activity. The initial overpotential under vis‐NIR light is 33 mV with a Tatel slope of 101 mV/dec while the overpotential is 150 mV at 10 mA cm⁻². The enhanced catalyst activity is ascribed to samples with heterogeneous structures and changed morphology and composition. In addition, localized surface Plasmon resonance (LSPR) effect from the surface of samples resulted in the effective separation of electron‐hole pairs (photoelectric effect). Finally the photothermal effect generated from the absorbance of Au nanostructures in near‐infrared light increased the temperature of the catalyst. The synergy of structure, photoelectricity, and photothermal effect endows the catalyst with excellent photo‐assisted electrocatalytic activity.