Conversion of confined metal@ZIF-8 structures to intermetallic nanoparticles supported on nitrogen-doped carbon for electrocatalysis

摘要

We report a facile strategy to synthesize intermetallic nanoparticle (iNP) electrocatalysts via one-pot pyrolysis of a zeolitic imidazolate framework,ZIF-8,encapsulating precious metal nanoparticles (NPs).ZIF-8 serves not only as precursor for N-doped carbon (NC),but also as Zn source for the formation of intermetallic or alloy NPs with the encapsulated metals.The resulting sub-4 nm PtZn iNPs embedded in NC exhibit high sintering resistance up to 1,000 ℃.Importantly,the present methodology allows fine-tuning of both composition (e.g.,PdZn and RhZn iNPs,as well as AuZn and RuZn alloy NPs) and size (2.4,3.7,and 5.4 nm PtZn) of the as-formed bimetallic NPs.To the best of our knowledge,this is the first report of a metal-organic framework (MOF) with multiple functionalities,such as secondary metal source,carbon precursor,and size-regulating reagent,which promote the formation of iNPs.This work opens a new avenue for the synthesis of highly uniform and stable iNPs.