Pd-Coated Au Triangular Nanoprisms as Catalysts for Hot-Carrier-Driven Photochemistry

Bimetallic nanoparticle dyads consisting of a plasmonic core and a catalytic metal shell have attracted significant attention in the context of solar-driven photocatalysts. However, a pertinent design considering both the optical properties of the core and shell and the thickness of the shell material is scarce. Through experiments and simulations, we demonstrated that the photocatalytic efficiency of the Au triangular nanoprisms@Pd (AuTP@Pd) core@shell dyad largely depends on the thickness of the catalytic metal shell. For a lower thickness, the dyad showed enhanced photocatalytic activity compared to bare AuTPs. However, for a higher thickness, the dyad's catalytic activity reduced drastically and showed even lower catalytic activity than pristine AuTPs. From simulations, we showed that for a thin Pd layer, charge carriers were essentially generated at the Pd shell itself and thereby could be easily extracted and utilized. However, a thicker Pd shell screened the plasmonic core and reduced the charge-carrier formation. These findings will be relevant for the optimization of the bimetallic plasmonic catalyst design.