Impact on the Formation and Catalytic Property of Pt-Based Nanocatalysts by Galvanic Reaction with Co-Reduction Agents

It has been shown that controlling the morphology and composition of Pt-based nanocrystals can effectively enhance catalytic properties. We report a detailed study on the impact of using co-reducing agents in the galvanic replacement reaction (GRR) between Ag shell templates and Pt precursors to better control the morphology, composition, and resulting performance of the fabricated Pt-based catalysts. Mesoporous silica-supported silver shell-coated gold nanodumbbell nanostructures (AuNDB@Ag@mSiO2) are synthesized via reducing silver ions which have penetrated through the mSiO2 layer and then be deposited on the surface of the AuNDBs. These are used as templates and the morphology and optical properties of these templates can be adjusted by altering the amount of Ag+ in the depositing condition. The mSiO2 layer shows some flexibility and does not influence the silver shell formation on the surface of AuNDBs. Additionally, the thickness of the silver shell of the template and the strength of the reducing agent used in the GRR impact the morphology, composition, and catalysis performance of the resulting Pt-based catalysts. A plausible mechanism on those observations is studied and discussed.