Al3+leaching induced Co4+on CoFeAl layered double hydroxide for enhanced oxygen evolution reaction

Transition metal Co-based materials such as layered double hydroxides (LDHs) are recognized as the pre-catalysts that will undergo the electrochemical reconstruction under oxygen evolution reaction (OER) conditions, in which the formed high-valent Co4 thorn can offer high intrinsic activity. However, the controllable formation of highly active Co4 thorn species still remains challenging. Herein, we show that the leaching of Al3 thorn after OER activation successfully induces the high-valent Co4 thorn formed on CoFeAl LDH (CFA0.8-LDH/NF-200CV), which is confirmed by a series of physical characterization and electrochemical measurements. The reconstructed electrocatalyst CFA0.8-LDH/NF-200CV presents excellent OER performance with an overpotential of 222 mV at 10 mA cm 2 and a small Tafel slope of 25.4 mV dec 1. This work may enlighten the surface reconstruction and activity promotion with leachable cations to induce high-valent metal active sites of other electrocatalysts.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Transition metal Co-based materials, such as layered double hydroxides (LDHs), can undergo electrochemical reconstruction under oxygen evolution reaction (OER) conditions to form highly active Co4 species. However, controlling the formation of these species remains challenging. In this study, the leaching of Al3 after OER activation successfully induces the formation of high-valent Co4 species on CoFeAl LDH, leading to an electrocatalyst with excellent OER performance. This work provides insights into surface reconstruction and activity promotion using leachable cations to induce high-valent metal active sites in other electrocatalysts.