High catalytic performance of nano-flowered Mg-doped NiCo layered double hydroxides for the oxygen evolution reaction

Abstract

Layered double hydroxides (LDHs) are one of the ideal functional materials for the oxygen evolution reaction (OER) because of their special configuration and good electrochemical activity. Incorporating different divalent and trivalent metals into layered double hydroxides (LDHs) is an effective way to induce defects and generate abundant oxygen vacancies and adjust the morphology of the materials and thus enhance the intrinsic catalytic activity of the materials. In this work, a nano-flower-like Mg-doped NiCo-LDH (denoted as NiCoMg-LDH) was synthesized by a solvothermal method, and the effect of the molar ratio of Mg, Co and Ni on the electrochemical activity of NiCoMg-LDH was explored. The results showed that NiCoMg-LDH with the optimum molar ratio (Ni : Co : Mg = 3 : 3 : 0.3) exhibited excellent OER catalytic activity in 1.0 M KOH, with an overpotential of only 229 mV at a current density of 10 mA cm⁻², a small Tafel slope of 31.0 mV dec⁻¹, and an electrochemically active surface area (ECSA) of 410 cm². This work provides a facile but effective method to improve the OER performance of layered double hydroxides.