Engineering d-band center of iron single atom site through boron incorporation to trigger the efficient bifunctional oxygen electrocatalysis

Modulating the microenvironment of single-metal active sites holds excellent promises for developing highly efficiently oxygen electrocatalysts. Herein, by combining theoretical predictions and experiments, we reported a general strategy to engineer the electronic properties of iron-nitrogen-carbon (FeN4/C) catalysts via the incorporation of the boron (B) atom for achieving improved catalytic activity in oxygen electrocatalysis. Our theoretical results revealed that B modulation effectively tunes the d-band center of the iron (Fe) active site to optimize its adsorption strength with oxygenated species, greatly enhancing oxygen reduction reaction (ORR) and oxygen evolution reactions (OER) activity. Our experimental measurements then confirmed the above theoretical predictions: the as-synthesized B-doped FeN4/C (Fe-N4-B) material can perform as an eligible bifunctional catalyst for ORR and OER in alkaline media, and its catalytic activity even outperforms the commercial noble metal benchmarks. The present findings provide a promising strategy to further design the advanced catalysts for a wide range of electrochemical applications.