Single-atom catalysts (SACs) have become the most attractive frontier research field in heterogeneous catalysis. Since the atomically dispersed metal atoms are commonly stabilized by ionic/covalent interactions with neighboring atoms, the geometric and electronic structures of SACs depend greatly on their microenvironment, which, in turn, determine the performances in catalytic processes. In this review, we will focus on the recently developed strategies of SAC synthesis, with attention on the microenvironment modulation of single-atom active sites of SACs. Furthermore, experimental and computational advances in understanding such microenvironment in association to the catalytic activity and mechanisms are summarized and exemplified in the electrochemical applications, including the water electrolysis and O₂/CO₂/N₂ reduction reactions. Last, by highlighting the prospects and challenges for microenvironment engineering of SACs, we wish to shed some light on the further development of SACs for electrochemical energy conversion.

单原子催化剂（SAC）已成为非均相催化领域最有吸引力的前沿研究领域。由于原子分散的金属原子通常通过与相邻原子的离子/共价相互作用而稳定，因此SAC的几何结构和电子结构在很大程度上取决于其微环境，进而决定了催化过程的性能。在这篇综述中，我们将重点关注最近开发的SAC合成策略，并关注SAC的单原子活性位点的微环境调节。此外，在电化学应用中，包括水电解和O ₂，总结并举例说明了在与催化活性和机理相关的理解方面对这种微环境的理解的实验和计算进展。/ CO ₂ / N ₂还原反应。最后，通过重点介绍SAC的微环境工程的前景和挑战，我们希望对SAC用于电化学能量转换的进一步发展提供一些启示。