Unveiling the critical roles of metal dissolution electrodeposition in enhancing oxygen evolution reaction activity of Fe-NiOOH electrocatalysts

초록

Electrocatalysts for high-performance oxygen evolution reaction (OER) have suffered complex synthesis and activation processes, low electrical conductivity, and weak interactions with electrode substrates. To overcome these drawbacks, this study introduces metal dissolution electrodeposition (MDE) as a novel solution for fabricating OER catalysts. MDE involves the dissolution of a nickel substrate in an electrolyte containing Fe3+ ions, followed by the redeposition of the dissolved ions. Fe3+ delivers stable deposition of Ni2+ and Fe2+ due to their low reduction potential, enhancing adhesion of the catalyst with etched Ni substrate. Additionally, MDE allows the formation of abundant amorphous NiOOH phases, which can partially crystallize during activation through Fe de-intercalation, effectively forming Fe-integrated NiOOH. The optimized Fe-gamma-NiOOH catalyst synthesized via MDE demonstrated superior OER performance, with a low overpotential of 257 mV at a current density of 100 mA/cm2, a Tafel slope of 49.74 mV/dec, a charge transfer resistance of 551 m Omega, and a high active surface area of 13.23 mF/cm2. Notably, material prepared by MDE shows an overpotential improvement of approximately 50 mV compared to the 306 mV at 100 mA/cm2 achieved by conventional electrodeposition (CE) methods. These findings highlight the potential of MDE in developing high-performance OER catalysts, eliminating the need for nickel precursors.

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