Toward Stable Single-Atom Catalysts for Electro- and Thermocatalytic Applications: Conventional Approaches and Emergent Strategies

Single-atom catalysts (SACs) offer significant opportunities for maximizing metal utilization and tailoring active-site structures in electro- and thermocatalytic processes; however, their widespread implementation remains constrained by limited structural stability across synthesis, characterization, and operating conditions. This review critically examines the fundamental origins of SAC instability and systematically analyzes both conventional and emergent stabilization strategies reported in recent literature. The discussion integrates stability challenges arising during catalyst preparation, beam- and environment-induced transformations during characterization, and degradation pathways under electrochemical and high-temperature reaction conditions. Traditional approaches, including spatial confinement, coordination environment engineering, and strong and electronic metal−support interactions, are evaluated alongside emerging strategies such as plasma-based treatments, electrochemical potential control, ligand-assisted stabilization, ionic liquids, and atmosphere-dependent regeneration. By comparing stabilization mechanisms across electrocatalytic and thermocatalytic contexts, this review clarifies how distinct driving forces govern atom migration, dissolution, and aggregation. The major conclusion is that no single strategy universally ensures SAC stability; rather, rational integration of complementary stabilization principles, informed by operando insights, is required to achieve durable single-atom architectures. These insights provide a structured design framework for the development of robust SACs suitable for long-term energy and environmental applications.