Imaging Metal/Metal Oxide Electrocatalyst Transformations in Liquids

Recently, in-situ liquid-phase transmission electron microscopy (LP-TEM) attracts huge interest for investigations of heterogeneous electrocatalysis. In this Review, recent applications of in situ LP-TEM in tracking the morphological and structural evolution of the metal/metal oxide-based electrocatalysts includes the nucleation, growth, and self-assembly of nanoparticles, high index facets, and core–shell structure formation. In addition, the electrodeposition, electrochemical degradation and corrosion mechanisms are discussed. Besides, we also summarize and identify the intermediates and active sites during electrocatalytic water splitting reactions and CO2 electroreduction. Finally, the challenge and future developments in this direction are proposed. It is hoped that the Review offers guidelines and future perspectives for designing efficient electrocatalysts based on the in situ or operando LP-TEM.