Acid-etched layered double hydroxides with rich defects for enhancing the oxygen evolution reaction.

Water splitting is promising for energy storage and conversion, but the sluggish oxygen evolution reaction (OER) hinders its wide application. The search for efficient and low-cost electrocatalysts for oxygen evolution has been pursued owing to their significance for green energy generation and storage. Layered Double Hydroxide (LDH) based materials are promising for the OER to improve this weakness. However, the wide application of LDHs is limited by their electronic properties and active sites. Here we report a simple and promising method to improve the OER catalytic activity via an acid-base reaction, which resulted in an exfoliation process and multiple defects including Co, Fe and O vacancies. The acid etched LDHs exhibit better oxygen evolution performance than the pristine LDHs under alkaline conditions with a small Tafel slope and good durability. The acid etching improves the electronic structure and provides more active sites, which results in significant enhancement of OER activity. This work will open up a novel and inexpensive way to improve the catalytic performance in an alkaline substance.