Abstract
Particle sintering is one of the most significant impediments to functional nanoparticles in many valuable applications especially catalysis. Herein, we report that sintering-resistant nanoparticle systems can be realized through a simple materials-design which maximizes the particle-to-particle traveling distance of neighbouring nanoparticles. As a demonstration, Pt nanoparticles were placed apart from each other in wide-mouthed compartments tailored on the surface of self-assembled silica nanosheets. These Pt nanoparticles retained their particle size after calcination at elevated temperatures because the compartment wall elongates the particle-to-particle traveling distance to preclude the possibility of sintering. Moreover, these Pt nanoparticles in wide-mouthed compartments were fully accessible to the environment and exhibited much higher catalytic activity for CO oxidation than the nanoparticles confined in the nanochannels of mesoporous silica. The proposed materials-design strategy is applicable not only to industrial catalysts operating in harsh conditions, but also opens up possibilities in developing advanced nanoparticle-based materials with sustained performance.
Highlights
A proof-of-concept demonstration was implemented by utilizing dendrimer-encapsulated Pt NPs (PtDEN) as the active component (Supplementary Fig. S1)[22,26], and three kinds of silica supports with different topology/ nanostructures
The compartment-rich support (CMPT) was consisted of three-dimensionally assembled silica nanosheets which afforded a large number of compartments (60–80 nm deep) with the top ends widely open (10–80 nm)[27]
The transmission electron microscopy (TEM) images revealed that the Pt particle size in Pt/CMPT was at 1.7 ± 0.4 nm, nearly unaffected by the high-temperature calcination, and no large Pt aggregates were observed throughout the support particles (Fig. 3d,g and Supplementary Fig. S6c)
Summary
There was negligible difference in Pt particle size for the obtained products, PtDEN/CMPT, PtDEN/SBA15 and PtDEN/NS (Fig. 3a,b and c; Supplementary Fig. S5). These supported PtDENs were calcinated in air at 550 °C for 4 h to eliminate the dendrimer components and expose the active surface of Pt NPs28,29, yielding Pt/CMPT, Pt/SBA15 and Pt/NS (Fig. 3d,e and f).
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