Bioinspired NiFe–gallate metal–organic frameworks for highly efficient oxygen evolution electrocatalysis

Abstract

We report the synthesis of a bioinspired NiFe–gallate metal–organic framework on carbon paper using gallic acid (GA) as the organic ligand, nickel chloride hexahydrate and iron(II) chloride tetrahydrate as metal sources by a one-step hydrothermal method. The as-prepared NiFe–GA on carbon paper exhibits excellent oxygen evolution reaction (OER) performance, which requires overpotentials of 185 mV and 236 mV to achieve 10 mA cm⁻² and 100 mA cm⁻² in 1.0 M KOH, respectively. In situ electrochemical and density functional theory calculation results reveal that the presence of Fe and GA favors the generation of active oxygen species and the catalytic active Ni- and Fe-sites facilitate the charge transport to adsorbed OH_ad reducing the activation barrier of OH_ad deprotonation to form O_ad intermediates, thereby contributing the superior OER performance.