Computational atomic-scale design and experimental verification for layered double hydroxide as an efficient alkaline oxygen evolution reaction catalyst

Abstract

Electrochemical water splitting is one of the most efficient techniques to produce hydrogen in an environmentally friendly way. However, a sluggish anodic reaction, namely oxygen evolution reaction (OER), requires the use of an efficient electrocatalyst for achieving economic hydrogen production. Transition-metal-based layered double hydroxides (LDHs) are promising electrocatalysts for reducing the overpotential of OER in alkaline electrolyte, which is essential for efficient water electrolysis. Nickel-iron-based LDHs (Ni-Fe LDH) have been regarded as the best OER electrocatalysts under alkaline conditions. Hence, a number of research studies have been conducted on further improving the electrocatalytic performance of Ni-Fe LDH. Although the chemical blending of other transition metals with Ni-Fe-LDH is a simple and reliable strategy to enhance the OER activity of Ni-Fe-LDH, a systematic investigation on designing Ni-Fe-LDH with different additional elements is still lacking. In addition, the design of multi-metallic LDH compound via only experimental method is very costly and time-consuming process. In this study, atomic-scale computational and experimental studies are performed to design OER electrocatalysts including unary, binary, and ternary LDH compounds consisting of Ni, Fe, Al, and Co. Density functional theory calculations predict that Ni-Fe-Co ternary LDH can lead to the lowest overpotential for alkaline OER among various computationally modeled LDH systems. Further, experimental verifications successfully demonstrate the computational prediction wherein Ni-Fe-Co-LDH exhibits superior catalytic performance compared with Ni-Fe-LDH and benchmark IrO2 catalysts.