ACS Applied Materials & Interfaces · 2016 · 36 citations · 60 references
The design and engineering of earth-abundant catalysts that are both cost-effective and highly active for water splitting are crucial challenges in a number of energy conversion and storage technologies. In this direction, herein we report the synthesis of Fe<sub>3</sub>O<sub>4</sub>@NiFe<sub>x</sub>O<sub>y</sub> core-shell nanoheterostructures and the characterization of their electrocatalytic performance toward the oxygen evolution reaction (OER). Such nanoparticles (NPs) were produced by a two-step synthesis procedure involving the colloidal synthesis of Fe<sub>3</sub>O<sub>4</sub> nanocubes with a defective shell and the posterior diffusion of nickel cations within this defective shell. Fe<sub>3</sub>O<sub>4</sub>@NiFe<sub>x</sub>O<sub>y</sub> NPs were subsequently spin-coated over ITO-covered glass and their electrocatalytic activity toward water oxidation in carbonate electrolyte was characterized. Fe<sub>3</sub>O<sub>4</sub>@NiFe<sub>x</sub>O<sub>y</sub> catalysts reached current densities above 1 mA/cm<sup>2</sup> with a 410 mV overpotential and Tafel slopes of 48 mV/dec, which is among the best electrocatalytic performances reported in carbonate electrolyte.
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