Ligand Engineering of Colloidal Nanocrystals for Electrocatalysis

Colloidal nanocrystals offer a versatile platform for electrocatalysis because their size, composition, morphology, and surface structure can be precisely tailored through solution‐phase synthesis. Among the available design parameters, surface ligands have emerged as central molecular regulators that govern nanocrystal nucleation, growth, facet stabilization, defect formation, heterostructure construction, and interfacial microenvironments. This review provides a mechanism‐oriented overview of ligand engineering in colloidal nanocrystals for electrocatalysis. We summarize major ligand classes and discuss how ligand‐directed and ligand‐transduced strategies enable programmable control over facets, strain, defects, phase evolution, and multicomponent architectures, thereby improving catalytic activity, selectivity, and durability across key reactions, including oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), carbon dioxide reduction reaction (CO 2 RR), nitrogen reduction reaction (NRR), and liquid fuel oxidation. We further highlight current challenges in understanding dynamic ligand evolution under operating conditions and outline future opportunities in operando characterization, microenvironment engineering, dynamic ligand systems, and scalable nanocrystal architectures for next‐generation electrochemical energy conversion in sustainable energy and chemical transformation technologies.