Trace Metal Loading of B‐N‐Co‐doped Graphitic Carbon for Active and Stable Bifunctional Oxygen Reduction and Oxygen Evolution Electrocatalysts

Abstract

AbstractUnderstanding the structure‐property relations of non‐precious metal heteroatom co‐doped carbon electrocatalysts exhibiting high activity as well as long‐term durability for both ORR and OER remains challenging but is indispensable for the development of bifunctional ORR/OER electrocatalysts. We propose B‐N‐co‐doped graphitic 2D carbon nanostructures impregnated with controlled amount of transition metals (M‐BCN; M=Co, Ni, Fe, Cu) as bifunctional ORR/OER electrocatalysts. Co‐BCN outperformed the Ni‐, Fe‐, Cu‐based BCN catalysts exhibiting potential values of 0.87 V and 1.62 V at −1 mA/cm2 and 10 mA/cm2 during ORR and OER, respectively. Importantly, Co‐BCN shows bifunctional cyclic stability (Δη; EOER−EORR=0.75 V) of up to 300 cycles in 1 M KOH for a duration of 20 h with total activity loss of only 10.2 % (ORR) and 6.2 % (OER), respectively. A low loading of the metal precursors was used to preserve porosity and to facilitate the formation of metal nanoparticles or M−NxB/C type species embedded in the graphitic carbon layers. The B‐N‐co‐doped graphitic layers also protect the embedded metal nanoparticles explaining the observed long‐term stability.