Ultrathin NiFeZn-MOF nanosheets containing few metal oxide nanoparticles grown on nickel foam for efficient oxygen evolution reaction of electrocatalytic water splitting

Abstract

Usually, metallic organic frameworks (MOFs) based electrocatalysts are prepared by pyrolysis of MOFs. And it is improved that the research on direct use of MOFs as electrocatalysts through the development of two-dimensional (2D) shaped MOFs direction is feasible. In this paper, a kind of ultrathin NiFeZn-MOF nanosheets containing few metal oxide nanoparticles grown on nickel foam (NiFeZn-MNS/NF) are successfully synthesized, and they are used as catalyst for the oxygen evolution reaction (OER) and overall water splitting. The NiFeZn-MNS/NF catalyst behaves the most excellent electrocatalytic performance with the best overpotential of 350 mV at 50 mA cm−2 and has the best current density stability with the 5% drop of the initial polarization current density at the end of 120 h. The voltage of NiFeZn-MNS/NF as a bifunctional overall water-splitting catalyst is 1.52 V at the current density of 10 mA cm−2, which is superior to commercial noble metal electrocatalytic combination of RuO2/NF(+)//Pt-C/NF(−)(1.63 V). The structure and morphology of the nanosheets and the synergistic effect of nickel, iron and zinc ions enhance the catalytic activity. While the addition of zinc ion promotes the rapid growth of nanosheets on nickel foams, which further improves the stability of nanosheets.