Taming the stability of Pd active phases through a compartmentalizing strategy toward nanostructured catalyst supports

Abstract

The design and synthesis of robust sintering-resistant nanocatalysts for high-temperature oxidation reactions is ubiquitous in many industrial catalytic processes and still a big challenge in implementing nanostructured metal catalyst systems. Herein, we demonstrate a strategy for designing robust nanocatalysts through a sintering-resistant support via compartmentalization. Ultrafine palladium active phases can be highly dispersed and thermally stabilized by nanosheet-assembled γ-Al 2 O 3 (NA-Al 2 O 3) architectures. The NA-Al 2 O 3 architectures with unique flowerlike morphologies not only efficiently suppress the lamellar aggregation and irreversible phase transformation of γ-Al 2 O 3 nanosheets at elevated temperatures to avoid the sintering and encapsulation of metal phases, but also exhibit significant structural advantages for heterogeneous reactions, such as fast mass transport and easy access to active sites. This is a facile stabilization strategy that can be further extended to improve the thermal stability of other Al 2 O 3-supported nanocatalysts for industrial catalytic applications, in particular for those involving high-temperature reactions.