A Self-Assembled Hetero-Structured Inverse-Spinel and Anti-Perovskite Nanocomposite for Ultrafast Water Oxidation

Spinel and perovskite with distinctive crystal structures are two of the most popular material families in electrocatalysis, which, however, usually show poor conductivity, causing a negative effect on the charge transfer process during electrochemical reactions. Herein, a highly conductive inverse spinel (Fe₃O₄) and anti-perovskite (Ni₃FeN) hetero-structured nanocomposite is reported as a superior oxygen evolution electrocatalyst, which can be facilely prepared based on a one-pot synthesis strategy. Thanks to the strong hybridization between Ni/Fe 3d and N 2p orbitals, the Ni₃FeN is easily transformed into NiFe (oxy)hydroxide as the real active species during the oxygen evolution reaction (OER) process, while the Fe₃O₄ component with low O-p band center relative to Fermi level is structurally stable. As a result, both high surface reactivity and bulk electronic transport ability are reached. By directly growing Fe₃O₄/Ni₃FeN heterostructure on freestanding carbon fiber paper and testing based on the three-electrode configuration, it requires only 160 mV overpotential to deliver a current density of 30 mA cm⁻² for OER. Also, negligible performance decay is observed within a prolonged test period of 100 h. This work sheds light on the rational design of novel heterostructure materials for electrocatalysis.