Electrochemical water splitting has attracted great attention due to the discovery of highly efficient, low-cost, and stable electrocatalysts such as 3d transition metal oxides, phosphides, and layered double hydroxides (LDH). In this study, we directly deposited cobalt-iron (CoFe) LDH on metal-organic-frameworks (MOF) derived cobalt phosphide, possessing high surface area and OER responsive, without using binder on nickel foam substrate. The CoFe LDH-CoP heterostructures were grown on the porous nickel foam (1 cm x 1 cm) substrate using a facile phosphorization of MOF materials of Co-ZIF-L followed by fast electrodeposition method. As-prepared electrode was directly employed as an oxygen evolution reaction (OER) after activation of LDH, which shows a remarkable current density at a low overpotential in a 1 M KOH electrolyte solution. The OER electrode exhibits an excellent catalytic performance with an overpotential of 370 mV at a current density of 100 mA cm-2 without iR compensation. Also, Tafel slope of CoFe LDH-CoP exhibited less than 60 mV-1 with 100% iR compensation, which displayed catalyst performance surpassing that of CoP and CoFe LDH on nickel foam. Moreover, CoFe LDH-CoP also demonstrated an excellent long-term stability more than 2000 cycle and over 24 h operation in 1 M KOH electrolyte. These easy-to-synthesize and noble metal free hierarchical structure could also be applicable for various energy materials applications.

Cobalt-iron layered double hydroxide on metal–organic-framework derived cobalt phosphide electrodes for efficient oxygen evolution reaction

2019 Fall National Meeting

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