Effect of Iron Loading on Controlling Fe/N−C Electrocatalyst Structure for Oxygen Reduction Reaction

Abstract

AbstractFe/N−C electrocatalysts were synthesized using iron chloride, ammonium chloride, glycine, and acetylene black by pyrolysis at 900 °C under nitrogen atmosphere. Acid leaching process successfully removed non‐bonded Fe which confirmed by X‐ray Diffraction (XRD) analysis. Deconvolution of Raman spectra showed that Fe1−NC had a high ID/IG value of 1.37 due to the presence of defect sites and disordered carbon structure. The calculation result showed that higher Fe loading leads to the carbon structure rearrangement into graphitic structure, thus reducing the ID/IG to 1.06. The cyclic voltammetry (CV) test of Fe1−NC shows the best catalytic performance for oxygen reduction reaction (ORR) compared to higher Fe‐loading samples. Rearrangement in the carbon structure into the more graphitic led to active sites decrease, thus resulted in a decrease of IORR from 4.6 to 1.7 μA for Fe1−NC and Fe20−NC. This study indicates that optimum iron loading could be an essential factor in improving catalyst performance.