Facile fabrication of Cu-based alloy nanoparticles encapsulated within hollow octahedral N-doped porous carbon for selective oxidation of hydrocarbons

Hollow carbon materials with versatile chemical compositions and complicated shell architectures hold great promise in heterogeneous catalysis. However, it is a daunting challenge to synthesize metal alloy nanoparticles (NPs) supported by hollow nanostructures. Herein, we present a simple approach for facile fabrication of Pd–Cu alloy NPs embedded in hollow octahedral N-doped porous carbon (Pd–Cu@HO-NPC). The hollow material is derived from HKUST-1 coated by an imidazolium-based ionic polymer (ImIP). Water-sensitive HKUST-1 is simultaneously removed in the process of anion exchange between bromide in the ImIP shell and tetrachloropalladate in aqueous medium. The released Cu(ii) ions and exchanged Pd(ii) ions serve as Cu and Pd sources in the subsequent pyrolysis. The resultant Pd–Cu@HO-NPC exhibits high catalytic activity, selectivity, stability and recyclability in the aerobic oxidation of hydrocarbons. More attractively, the synthetic strategy is of excellent generality, and could be extended to the synthesis of Cu-based bimetallic and trimetallic alloy NPs, such as Pt–Cu@HO-NPC and Pd–Pt–Cu@HO-NPC. This work highlights the superiority of water-sensitive metal–organic frameworks in the ingenious design of hollow carbon materials incorporated with well-dispersed metal alloy NPs.