Bimetallic ZIFs derived 3D acetylene black loading La2O3/Co bifunctional ORR/OER catalysts

Abstract

A new type of acetylene black (AB) loading La2O3-Co/AB catalyst derived from rare earth (RE) La-doped zeolite imidazole framework-67 (ZIF-67) was prepared by composite synthesis strategy to make up for the defects of the weak activity and conductivity of single transition metal catalysts. The different coordination forms of La and cobalt hinder the growth of La-ZIF-67 crystals and promote the exposure of active sites, and the La2O3 in the pyrolysis product improves the stability of the catalyst. The introduction of AB provided abundant anchor sites to facilitate the heterojunctions formation and the electronic transfer at the interface. Remarkably, La2O3-Co/AB showed high ORR half-wave potential and low OER overpotential, which is believed to benefit from the rich CoNx local environment, heterostructure with internal electric field and oxygen vacancies.