FeN4 Sites Embedded into Carbon Nanofiber Integrated with Electrochemically Exfoliated Graphene for Oxygen Evolution in Acidic Medium. Issue 26 (5th August 2018) - Lei, Chaojun
Abstract: Development of inexpensive and efficient oxygen evolution reaction (OER) catalysts in acidic environment is very challenging, but it is important for practical proton exchange membrane water electrolyzers. A molecular iron–nitrogen coordinated carbon nanofiber is developed, which is supported on an electrochemically exfoliated graphene (FeN4 /NF/EG) electrocatalyst through carbonizing the precursor composed of iron ions absorbed on polyaniline‐electrodeposited EG. Benefitting from the unique 3D structure, the FeN4 /NF/EG hybrid exhibits a low overpotential of ≈294 mV at 10 mA cm −2 for the OER in acidic electrolyte, which is much lower than that of commercial Ir/C catalysts (320 mV) as well as all previously reported acid transitional metal‐derived OER electrocatalysts. X‐ray absorption spectroscopy coupled with a designed poisoning experiment reveals that the molecular FeN4 species are identified as active centers for the OER in acid. The first‐principles‐based calculations verify that the FeN4 –doped carbon structure is capable of reducing the potential barriers and boosting the electrocatalytic OER activity in acid. Abstract : Highly active FeN4 sites for acidic electrochemical water oxidation : A novel 3D electrocatalyst based on molecular iron–nitride coordinated carbon nanofiber supported on electrochemically exfoliated graphene is successfully synthesized for electrocatalytic oxygen evolution from water splitting in acid. Highly dispersed FeN4 sites are identified as the active centers for the acidic oxygen evolution reaction.