ZIF-67-templated synthesis of core-shell-structured POP@MOF composite derived porous carbon with embedding FeCo alloy nanoparticles as high-performance bifunctional oxygen electrocatalysts

Abstract

Abstract Herein, Fe-phthalocyanine-based conjugated microporous polymer (Fe-Phth-CMP) coated metal organic framework (ZIF-67) composites, namely Fe-Phth-CMP@ZIF-67, were facilely prepared via a rational and effective solid-phase synthesis method, in which, ZIF-67 worked as both precursors and templates. Upon carbonization, these special composites, with controllable morphology similar to ZIF-67 and adjustable Fe/Co molar ratio, can be further converted into N-doped porous carbons embedded with highly dispersed FeCo alloy and Fe/Co–N active sites. The optimal catalyst (denoted as P2Z3-900, prepared in a mass ratio of mPOP: mZIF = 2 : 3) features hierarchical pore structure which could significantly enhance the mass transfer efficiency and promotes the exposure of active sites, leading to high ORR and OER activity in alkaline conditions, simultaneously. For example, P2Z3-900 presents a half-wave potential (E1/2) of 0.81 V (vs RHE) with a diffusion-limited current density of 5.56 mA cm−2, comparable to commercial Pt/C (0.83 V and 5.60 mA cm−2), but much better than other prepared control samples. The Eonset of OER at 10 mA cm−2 reaches 1.60 V with a small Tafel slope of 57 mV dec−1. More importantly, the current synthetic method offers a rational strategy to structure-, morphology-, and element composition-controlled porous carbons, thereby finely regulating the property for efficient catalysis.