High-Performance CoAl–LDH Catalyst for Oxygen Evolution Reaction

Abstract

Developing cost-effective and sustainable green metal-based materials to substitute precious metal catalysts in the oxygen evolution reaction (OER) is a promising but challenging task. In this study, we propose a facile and ecofriendly coprecipitation method combined with a following hydrothermal treatment to synthesize a kind of monodisperse CoAl–LDH catalyst. The obtained nanoflakes are well water-dispersible and show regular morphology with an average particle size of about 179 nm. More importantly, an ultrathin thickness of approximately 2.3 nm of the as-prepared nanoflakes was achieved by controlling the temperature and duration of hydrothermal treatment without any surface modification. The excellent particle dispersibility and ultrathin thickness of the products make these nanoflakes to expose more active sites than the previously reported Co-based micro- and nanosized powders, thus allowing their OER catalytic activity to be enhanced significantly. Based on these obtained CoAl–LDH nanoflakes, a kind of CoAl–LDH/NF nanocomposite material has also been successfully fabricated, which exhibits outstanding catalytic performance in OER with a super low overpotential of only 200 mV at a current density of 10 mA·cm–2 and a small Tafel value of 49 mV/dec. Even at a much higher current density of 100 mA·cm–2, the detected overpotential can still be as low as 270 mV. This study presents a straightforward strategy for preparing cost-effective and high-efficiency LDH nanomaterials that may be used in the future industry of water electrolysis.