Design Strategies and in situ Infrared, Raman, and X‐ray Absorption Spectroscopy Techniques Insight into the Electrocatalysts of Hydrogen Energy System

The challenging sluggish reaction kinetics of hydrogen energy‐related electrocatalysis can be overcome via exploring electrocatalysts with high‐efficient activity and long‐term durability. However, the deficiency of comprehensive and in‐depth understanding of the evolution of the electrocatalysts, nature of active centers, intermediate species absorbed in the electrocatalysts, and the reaction pathway during the electrocatalytic processes seriously limits the elucidation of the composition/structure–activity relationship of electrocatalysts. To this end, plenty of powerful in situ techniques that can provide atomic/molecular information are employed to bridge the understanding of fundamental mechanisms to the practical development of electrocatalysts. This review summarizes design strategies based on composition regulation and morphology design for tuning the electronic/geometric structures of electrocatalytic materials with improved activity and stability. Moreover, the recent application of in situ infrared, Raman, and X‐ray absorption spectroscopy is elaborated with emphases on tracking the dynamic evolution during electrocatalysis and building a link between the composition/structure and activity of electrocatalysts. Finally, the current challenges and future perspectives for in situ monitoring techniques to gain an understanding more deeply and comprehensively in the hydrogen energy‐related electrocatalysis are proposed. This review provides insights into the rational optimization of electrocatalysts and inspire the unraveling mechanism of the enhanced electrocatalytic performance in future research.