Iron phthalocyanine with coordination induced electronic localization to boost oxygen reduction reaction.

Chen, Kejun; Liu, Kang; An, Pengda; Li, Huangjingwei; Lin, Yiyang; Hu, Junhua; Jia, Chuankun; Fu, Junwei et al. · Nat Commun · 2020

basic_science · Level V

Where this comes from

Abstract

Iron phthalocyanine (FePc) is a promising non-precious catalyst for the oxygen reduction reaction (ORR). Unfortunately, FePc with plane-symmetric FeN<sub>4</sub> site usually exhibits an unsatisfactory ORR activity due to its poor O<sub>2</sub> adsorption and activation. Here, we report an axial Fe-O coordination induced electronic localization strategy to improve its O<sub>2</sub> adsorption, activation and thus the ORR performance. Theoretical calculations indicate that the Fe-O coordination evokes the electronic localization among the axial direction of O-FeN<sub>4</sub> sites to enhance O<sub>2</sub> adsorption and activation. To realize this speculation, FePc is coordinated with an oxidized carbon. Synchrotron X-ray absorption and Mössbauer spectra validate Fe-O coordination between FePc and carbon. The obtained catalyst exhibits fast kinetics for O<sub>2</sub> adsorption and activation with an ultralow Tafel slope of 27.5 mV dec<sup>-1</sup> and a remarkable half-wave potential of 0.90 V. This work offers a new strategy to regulate catalytic sites for better performance.