Rapidly Constructing Multiple AuPt Nanoalloy Yolk@Shell Hollow Particles in Ordered Mesoporous Silica Microspheres for Highly Efficient Catalysis

In this work, for the first time, AuPt alloy yolk@shell hollow nanoparticles (NPs) were constructed and simultaneously embedded into hollow interiors of a mesoporous silica microsphere based on a rapid aerosol process (AuPt@SiO2). Resin nanospheres were utilized both as a hard template to create hollow interiors inside the mesoporous silica microspheres and as carriers to transport pregrown metal nanocrystals, AuPt alloy dusters, into the microspheres. Calcination removes the resin nanospheres and causes metal nanocrystals to embed into the hollow interiors of the silica microspheres. Due to the unique yolk@shell hollow structure of the AuPt nanoalloy, ordered mesopores (67 nm) in the silica support, the synergetic effect between the AuPt alloy and the high surface area and pore volume of the microspheres, the AuPt@SiO2 spheres showed an excellent catalytic performance for styrene epoxidation with the conversion and selectivity of 85% and 87%, respectively. Notably, the novel catalyst showed a stable catalytic performance after five cycles of usage, suggesting the possible practical applications of the AuPt nanoalloy catalyst. In addition, the catalyst also exhibited a higher activity than the commercial Pt/C catalyst for the reduction reaction of 4-nitrophenol. The approach reported in this study could potentially be used to simplify the fabrication process of yolk@shell or hollow metal nanospheres, facilitating encapsulation of monometallic and multimetallic metal nanocrystals with various nanostructures and compositions into porous supports and thus guiding the design of catalysts with a special structure and high-performance.