Electrospun pan‐derived carbon nanofibers embedded with NiCoFeW‐based High‐entropy oxides for electrocatalytic oxygen evolution reaction

Abstract

High‐entropy oxides composed of Ni, Co, Fe, W, and a fifth transition element (Mo, Mn, or Cu) were integrated into electrospun polyacrylonitrile nanofibers to form porous nitrogen‐doped carbon membranes for the oxygen evolution reaction. Gas‐assisted electrospinning enabled uniform dispersion of high‐entropy oxide nanoparticles within the polyacrylonitrile matrix, while calcination at 800°C produced conductive carbon frameworks embedding crystalline high‐entropy oxides with homogeneous elemental distribution. Structural and surface analyses confirmed the preservation of high‐entropy oxide phases, catalytic graphitization of the carbon matrix, and strong interfacial bonding between metal oxides and carbon. Among all compositions, Mo‐HEO@NC exhibited the lowest overpotential (≈240 mV at 10 mA cm −2 ) and smallest charge‐transfer resistance (≈2177 Ω), outperforming Cu‐ and Mn‐containing counterparts. The enhanced activity originated from Mo‐induced electronic modulation, increased oxygen‐vacancy density, and accelerated charge transport. The combination of multicomponent high‐entropy oxides with electrospun N‐doped carbon nanofibers establishes a robust route toward efficient, earth‐abundant oxygen evolution reaction electrocatalysts with high stability and tunable electronic properties.