Constructing La-doped ultrathin Co-based nanostructured electrocatalysts for high-performance water oxidation process

Constructing highly efficient and low cost electrocatalysts for oxygen evolution reaction (OER) is pivotal to various energy storage and conversion devices. In this work, five different rare earth (RE) metals doped (La, Ce, Pr, Nd, Er) Ag-nanoparticles-decorated α-Co(OH)2 nanostructured electrocatalysts, which are grown on nickel foam (NF), are successfully prepared by a facile one-step hydrothermal approach. It is found that La-doped 2D ultrathin (∼2.0 nm) CoAg nanosheets arrays (denoted as La–CoAg/NF) can demonstrate the highest electrochemical activity towards OER in 1 M KOH solution among these RE-doped electrocatalysts. It delivers the lowest overpotential at 10 mA cm−2 (233 mV), the smallest Tafel slope (44.3 mV dec−1) and extraordinary stability for 35 h with no significant change during harsh OER process. The reasons for the enhanced performance may come from unique ultrathin 2D nanostructure and La-induced strong electronic interaction among Co, Ag, and La atoms. This work provides an essential insight to the development of RE-metal doped electrocatalysts for energy conversion.