Bamboo‐Like Carbon Nanotube‐Encapsulated Fe2C Nanoparticles Activate Confined Fe2O3 Nanoclusters Via d‐p‐d Orbital Coupling for Alkaline Oxygen Evolution Reaction

Abstract The efficient anion exchange membrane water electrolysis is challenging with low cell voltage and long‐term stability at large current density, due to the unstable anodic oxygen evolution reaction (OER). Fe‐based electrocatalysts are potential candidates for the anodic OER. In Fe‐based materials, iron oxides always show better stability in alkaline solution but lower OER activity. However, the catalysts in previous study are difficult to continuously and effectively activate iron oxides supported on carbon during electrocatalysis. Herein, a new class of electrocatalyst: bamboo‐like carbon nanotubes (B‐CNT)‐encapsulated Fe 2 C nanoparticles (NPs) supported Fe 2 O 3 nanoclusters (NCs), named Fe 2 O 3 /B‐CNT@Fe 2 C is reported. Theoretical calculations and experimental results reveal that B‐CNT‐encapsulate Fe 2 C NPs activate Fe 2 O 3 NCs by the d‐p‐d orbital coupling, thereby weakening the adsorption of OOH* intermediate during OER process. The electrolyzer based on the electrocatalyst requires only 1.48 V to reach 1.0 A cm −2 and shows a long‐term stability at 1.0 A cm −2 for 1600 h, comparable to the best‐reported values for the anion exchange membrane water electrolyzer (AEMWE).