Several Key Factors for Efficient Electrocatalytic Water Splitting: Active Site Coordination Environment, Morphology Changes and Intermediates Identification

Water-splitting has emerged as a promising alternative strategy to produce clean hydrogen fuel. However, current electrocatalytic water splitting suffers from sluggish kinetics, thus developing efficient electrocatalysts is crucial. Identifying reaction centers discloses the reaction mechanism and will undoubtedly facilitate the design and optimization of efficient water splitting electrocatalysts. This review summarizes several advances involving the identification of the actual active sites and intermediates capture on the catalytic surface. The morphology and valence states change on 2D materials are chose to illustrate how structural evolution affect catalytic activity. Specifically, in situ/ex situ electron microscopy techniques that used for the characterization of catalytic sites, and spectroscopy techniques that used to detect active intermediates at the molecular level are highlighted. In addition, several perspectives, such as the development of new in situ techniques and electrokinetic analysis methods, are emphasized to shed light on future research.