Prussian blue analogues derived electrocatalyst with multicatalytic centers for boosting oxygen reduction reaction in the wide pH range

Abstract

Due to the complex of oxygen reduction reaction (ORR), designing catalysts with multicatalytic centers is considered as a promising way for boosting the ORR. Herein, a multicatalytic centers electrocatalyst Fe3C/Mn3O4 encased by N-doped graphitic layers (FeMn PDA-900) is synthesized using iron manganese Prussian blue analogues and dopamine as the precursor. It exhibits a half-wave potential (E1/2) of 0.86 V for ORR and yields of H2O2 lower than 5% in 0.1 M KOH. Moreover, the prepared catalyst has also shown high catalytic ORR performance in both acidic and neutral electrolyte solutions, which exhibits the potential application in both the proton exchange membrane fuel cell and the microbial electrolysis cell. It is found that the good performance can be well explained by proton-coupled electron transfer mechanism due to the multicatalytic centers from Fe-Nx, Fe3C and Mn3O4 for providing enough active sites at the same time and the N-doped graphitic layers as a bridge for facilitating the electron transfer between the interfaces of Fe3C/Mn3O4 nanoparticles, which paves the way for protons and electrons transfer simultaneously and rapidly, and thus lowing the energy barrier and facilitating the ORR process. Therefore, FeMn PDA-900 is a promising candidate to replace precious metal-based ORR electrocatalysts at the whole pH range.