Gold Nanobipyramids Coated with Silver–Platinum Alloy Shells for Plasmonically Enhanced Photocatalytic Degradation of Methyl Orange

Plasmonic multimetal materials, consisting of a plasmonic core and a catalytic shell in a core–shell structure, often exhibit excellent catalytic performances. Such excellent performances arise from the synergistic collaboration between the plasmonic core's localized surface plasmon-excited hot electrons and the catalytically active sites of the catalytic shell. In this context, a trimetallic nanostructure was designed featuring gold nanobipyramids (AuNBP) with a silver–platinum alloy shell, serving as a plasmon-mediated photocatalyst for the degradation of methyl orange (MO) under visible and near-infrared light. By altering the concentrations of the surfactants hexadecyltrimethylammonium bromide (CTAB) and hexadecyltrimethylammonium chloride (CTAC), the resulting nanostructure can take on either island-like or shell-like morphology. In the model system of the photocatalytic reaction of MO, employing the synthesized nanoparticles as catalysts, the study investigated the reaction under xenon lamp illumination. The trimetallic nanostructure exhibited robust photocatalytic performances, surpassing AuNBP by a factor of 27.8. The transfer of plasmon resonance energy from AuNBP to the silver–platinum alloy layer, augmenting the generation of charge carriers, elucidates its outstanding photocatalytic performance. The obtained trimetallic nanostructure showcases promising potential applications in the realm of photocatalysis, contributing to the development of advanced plasmon-enhanced photocatalysts with enhanced efficiency and multifunctionality.