Constructing Mn‐Co‐Fe Ternary Metal Phosphides Nanosheet Arrays as Bifunctional Electrocatalysts for Overall Water Splitting

Abstract

Bifunctional electrocatalysts with high efficiency, stability, and distinguished performance have attracted more and more attention in the field of overall water splitting, while the composition and structure design are very essential for electrocatalysts with superb performance and low price. In this work, the heterostructure Mn‐Co‐Fe‐P nanoarrays is in situ grown on nickel foam (NF) by simple hydrothermal method and phosphating method. The resultant Mn‐Co‐Fe‐P catalyst has favorable electrocatalytic performance with the oxygen evolution reaction (OER) overpotential at 10 (100) mA cm⁻² of 192 (279) mV and the Tafel slope of 43.75 mV dec⁻¹, the hydrogen evolution reaction (HER) overpotential at 10 (100) mA cm⁻² of 98 (152) mV and the Tafel slope of 40.68 mV dec⁻¹, and the full voltage of 1.66 V at 100 mA cm⁻² when applied to overall water splitting. The 3D heterostructure provides more active sites, and the in situ growth improves the stability and conductivity of the catalyst. This binder‐free heterostructure electrocatalyst with excellent stability and catalytic performance is a promising bifunctional electrocatalyst candidate for overall water splitting.