Construction of rare-earth-modified layered double hydroxide heterostructures and enhancement of overall water splitting efficiency

Abstract

Layered double hydroxides (LDHs) play an important part in water splitting due to their advantages of easily adjustable composition and large specific surface area. However, due to their poor stability and inability to fully utilize their active sites, their performance is still unsatisfactory. In this study, we prepared a series of CoCe-LDH-TiO₂@C electrocatalysts with non-epitaxial heterostructures, which demonstrate excellent electrocatalytic performance in alkaline media. Among these, Co_0.1Ce_0.01-LDH-TiO₂@C exhibits the best HER and OER performance and is recognized as the target sample. Also, its stability exceeds 100 hours. When used in the overall water splitting test, at a current density of 10 mA cm⁻², the voltage is only 1.724 V. The excellent performance of Co_0.1Ce_0.01-LDH-TiO₂@C is closely related to the establishment of a heterostructure and an appropriate bimetallic ratio. The appropriate metal ratio provides more active sites, while the construction of the heterostructure facilitates charge transfer at the interface, reduces the kinetic energy barrier, and enhances the reaction rate.