Iron group elements (Fe, Co, Ni) in Electrocatalytic applications: Evaluation, characterization and prospects

Electrocatalysis represents a promising approach for addressing energy shortages and environmental concerns. The quest for electrocatalysts characterized by high activity, low cost, and excellent stability is pivotal to advancing the field of electrocatalysis. Notably, the extraordinary electronic structure of iron group elements (Fe, Co, Ni) has garnered significant attention. This work introduces the evaluation indexes of electrocatalytic reactions, and also analyzes in-suit/operando characterization techniques commonly used in the study of electrocatalytic processes. The review encompasses the application of iron group electrocatalysts in various reactions including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall water splitting (OWS), oxygen reduction reaction (ORR), nitrogen reduction reaction (NRR) and carbon dioxide reduction reaction (CO₂RR). Furthermore, the paper presents a summary of the reaction mechanisms underlying each electrocatalytic process. It also delves into the research progress of iron group elements in diverse electrocatalytic reactions, aimed at advancing the advancement of electrocatalysts which are more available and stable. Lastly, the paper examines the situation status, challenges, and future prospects of iron group electrocatalysts, offering insights into the evolving landscape of iron group materials and the design of commercially viable electrocatalysts.