Stabilizing Active Metal Nanoclusters within Mesopores via an Inner Surface-Confinement Strategy

Mesoporous support-encapsulated fine-size metal nanoclustersholdgreat potential for catalytic applications by virtue of their highreactivity and fast mass transport kinetics but suffer greatly fromparticle aggregation and/or sintering, especially under high reactiontemperatures. Here, we report an inner surface-confinement strategyto stabilize a variety of ultrafine metal nanoclusters (M = Pt, Pd,Ni, and Ag) inside mesoporous silica supports. The strategy is basedon the selective N functionalization of the inner surface of mesopores,which not only assures the direct growth of ultrafine metal nanoclusterstherein but also endows the active metal nanoclusters with excellentthermal stability via N-metal coordination. Remarkably, the mesopore-encapsulatedN-coordinated Pt nanoclusters are particularly selective for making & alpha;,& beta;-unsaturated alcohol, benefiting from their energeticallyfavored reaction pathway for end-on binding & alpha;,& beta;-unsaturatedaldehyde reactants and heterolytic dissociation of hydrogen. The syntheticmethodology is expected to provide new guidelines to improve the thermalstability of mesopore-encapsulated metal nanoclusters for superb catalysis.

Automated summary

An inner surface-confinement strategy for stabilizing ultrafine metal nanoclusters inside mesoporous silica supports is reported. The strategy involves the selective N functionalization of the inner surface of mesopores, resulting in direct growth of ultrafine metal nanoclusters and excellent thermal stability through N-metal coordination. This synthetic methodology provides new guidelines to enhance the thermal stability of mesoporous-encapsulated metal nanoclusters for superior catalysis.