Trends and industrial prospects of NiFe-layered double hydroxide for the oxygen evolution reaction

Improving the kinetics of the oxygen evolution reaction (OER) is paramount in boosting the overall energy efficiency of alkaline water electrolysis. NiFe-LDH based OER electrocatalysts lead the activity charts at lab-scale conditions (i.e., 1 M KOH, room temperature) and have thus attracted tremendous attention over the last decade. A summary and distillation of the accumulated knowledge is imperative to promote further rational design and active site modulation of the next-generation NiFe-LDH based OER electrocatalysts. Here, we present a detailed review, commencing with the commonly employed synthesis techniques and proceeding to discuss the structural evolution during operation, and strategies exploited to improve the OER activity. Emphasis is placed on operando investigations aiming to identify the active phases and active sites of NiFe-LDH during OER and to understand the reaction mechanism. Finally, we review the literature assessing the stability of the active sites under the harsh OER operating conditions and summarize the influencing factors. We conclude with future research directions required to bridge the gap between lab-scale testing and industrial application in large-scale devices.