Ultrathin Fe2O3 shell-encapsulated NiFe alloy nanoparticles embedded in tubular carbon matrix for enhanced oxygen evolution reaction

The exploitation of efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) is the key to the industrialization of the hydrogen production technology from water splitting. Herein, Ni1Fe2@Fe2O3 composites with core-shell structure embedded in Metaplexis japonica fluff-derived carbon microtube matrix (Ni1Fe2@Fe2O3@C) are prepared by nitrate soaking and subsequent high-temperature calcination, which are used to catalyze the OER. The existence of carbon matrix greatly prevents the agglomeration of metal particles and creates an efficient electron transfer path for OER. The synergy among the carbon matrix, Ni1Fe2 core and Fe2O3 shell together enhances the OER performance, thus endowing Ni1Fe2@ Fe2O3@C with the considerable catalytic activity with the overpotential of 271 mV at 10 mA cm-2 and a Tafel slope of 78 mV dec-1. Ni1Fe2@Fe2O3@C also shows good stability due to the double protection of metal particles by biomass carbon matrix and ultrathin Fe2O3 shell. The water splitting device composed of Pt/C as the cathode and Ni1Fe2@Fe2O3@C as the anode exhibits water splitting activity close to that of Pt/C || RuO2 system in alkaline medium, and the stability retention rate of the system reaches to 93 % after 30 h elec-trolysis.(c) 2022 Elsevier B.V. All rights reserved.