High entropy alloy/C nanoparticles derived from polymetallic MOF as promising electrocatalysts for alkaline oxygen evolution reaction

Abstract

Recently, high entropy alloy (HEA) based materials have been vigorously explored as viable catalysts in water electrolysis for their unique properties. However, the synthesis of efficient and robust high entropy catalysts remains a challenge. Here a facile and scalable approach is reported to synthesize advanced HEA (CoNiCuMnAl)/C nanoparticles from the polymetallic Metal–organic framework (MOF). The novel core-shell nanoarchitectures feature face-centered cubic HEA wrapped in ultra-thin carbon shell. The optimized catalyst (deposited upon Ni foam) boosted alkaline Oxygen evolution reaction (OER) (in 1.0 M KOH) with an ultralow overpotential of 215 mV at 10 mA/cm2 (also by a low Tafel slope of 35.6 mV dec−1). The enhanced performance is closely tied to surface reconstruction (i.e., formation of oxyhydroxide catalytic active species) and the high entropy effect, revealed by Fourier-transformed alternating current voltammetry (FTACV) and in-situ Raman spectrum analysis, in conjunction with Density Functional Theory (DFT) computations. Furthermore, the new design showed excellent long-term OER stability with negligible decay through 30 h testing (under 200 mA cm−2). The present work demonstrates the feasibility and advantage of utilizing highly efficient and durable high entropy alloys for catalyzing electrochemical water splitting process.