Single-crystalline layered double hydroxides with rich defects and hierarchical structure by mild reduction for enhancing the oxygen evolution reaction

The oxygen evolution reaction (OER) with sluggish reaction kinetics and large overpotential is the critical reaction in water splitting that is promising for energy storage and conversion. Layered double hydroxides (LDHs), due to their unique lamellar structure and flexibility of chemical component, are very competing material candidates for OER. Herein, the morphology structure and the electronic structure of LDHs were simultaneously tuned to improve the OER catalytic activity by mild solvothermal reduction using ethylene glycol. The increased surface area, the introduction of oxygen vacancies and the construction of hierarchical structure greatly enhanced the electro-catalytic activity of LDHs for OER. The as-prepared LDHs showed a lower over-potential as low as 276 mV at a current density of 10 mA cm−2, and a small Tafel slope of 40.3 mV dec−1 accompanied with good stability. This work provides an efficient way to the design and optimization of advanced catalysts in the future.