An integrated optimization of composition and pore structure boosting electrocatalytic oxygen evolution of Prussian blue analogue derivatives

Abstract

Exploring efficient and low-cost electrocatalysts for oxygen evolution reaction (OER) is of great importance for renewable energy-related systems. Prussian blue analogues (PBAs) are considered as promising precursors to derive advanced heteroatom-doped carbonaceous materials. However, the pyrolysis treatment usually results in an inevitable aggregation of active sites as well as the reduction of specific surface area, apart from the uncontrollable composition and morphology. Herein, we develop a straightforward synthetic protocol for fabricating highly-active OER electrocatalysts of Co7Fe3, Co, N-codoped carbon (Co7Fe3/Co@NC) by annealing trimetallic CoZnFe-PBA precursors. The surface modification of cobalt species over ZnFe-PBA effectively tailors the active composition for as-derived products, whereas Zn volatilization at a high temperature not only promotes the dispersion of active sites but also fabricates the formation of an intriguing hierarchical structure with multimodal porosity and high specific surface area. The integrated advantages of multinary composition and fabulous pore structure endow the elegantly-designed Co7Fe3/Co@NC with a remarkable catalytic performance towards OER in alkaline electrolyte, as evidenced by an overpotential of 290 mV without iR-correction at a current density of 10 mA cm−2 and impressive long-term durability. The present synthetic strategy offers valuable insights for developing highly-efficient PBAs-derived electrocatalysts with compositional multiplicity and interesting pore texture.