Enhanced Chemoselectivity in Pt–Fe@mSiO 2 Bimetallic Nanoparticles in the Absence of Surface Modifying Ligands

摘要

Noble metal-based bimetallic nanoparticles (NPs) synthesized using colloidal methods always contain organic capping agents. These NPs show high selectivities in many chemoselective hydrogenation reactions benefitting from both capping agents and secondary metals. However, it is challenging to separately identify the role of the secondary metal and the capping agents in the bimetallic NPs because the complete removal of the capping agents can often cause their aggregation or structural/compositional changes. Herein we report the synthesis of Pt~(5)Fe~(x)(x?=?1, 2 and 4) bimetallic NPs capped by an inorganic mesoporous silica (mSiO~(2)) shell, which could prevent NP aggregation during high-temperature treatment to remove capping agents. Using these Pt~(5)Fe~(x)@mSiO~(2)NPs with a clean surface, we could demonstrate the role played independently by the bimetallic composition in the selective hydrogenation of cinnamaldehyde and furfural. Understanding the functions of the secondary metal and the surface modifying ligands on the selectivity enhancement of bimetallic NPs is necessary for the design of high-performance chemoselective catalysts.