Self-supported Fe, Mn-co-doped NiCo2Se4 nanorods on nickel foam for enhanced electrocatalytic performance in wide pH range

Abstract

Synthesizing efficient and robust catalyst can reduce the energy barrier of overall-water-splitting (OWS) and pave the way for obtaining hydrogen energy. Herein, a novel self-supported Fe, Mn-co-doped NiCo2Se4 nanorod grown on nickel foam (Fe, Mn–NiCo2Se4/NF) was hydrothermally synthesized. The bimetallic doping can regulate the electronic structure to enhance intrinsic activity, while the nanorod arrays structure increased the active sites, consequently improving catalytic activity. In addition, the binder-free electrode can strengthen conductivity and stability. Therefore, Fe, Mn–NiCo2Se4/NF presents prominent OER activity with a low overpotential of 272 mV at 100 mA cm−2. Interestingly, the newly designed catalysts realize ultra-high HER efficiency in a universal-pH range, which requires overpotentials of 187 and 179 mV in 1.0 M KOH and 0.5 M H2SO4 to reach 100 mA cm−2, respectively. The cell potential of Fe, Mn–NiCo2Se4/NF as a bifunctional catalyst is 1.699 V at 100 mA cm−2 in 1.0 M KOH with outstanding stability for at least 180 h, surpassing many state of the art catalysts reported in literature. This work concludes that the bimetallic doping, nanorod arrays, and self-supported structure are promising strategies for preparing effective and stable catalysts for the production of hydrogen energy from water splitting reactions.