Recent advances in single-atom catalysts for high-performance carbon dioxide electroreduction: Synthetic strategies and electrochemical frontiers

The electrochemical carbon dioxide reduction reaction (CO₂RR) represents a cornerstone technology for mitigating greenhouse gas emissions while simultaneously producing value-added chemicals and fuels from a renewable carbon source. The development of this technology hinges on the design of highly active, selective, and stable electrocatalysts. Single-atom catalysts (SACs), which feature atomically dispersed metal centers anchored on a support material, have emerged as a frontier in catalysis science, offering unprecedented opportunities for CO₂RR. By maximizing atom-utilization efficiency and providing a unique, tunable coordination environment, SACs bridge the gap between homogeneous and heterogeneous catalysis, enabling both high performance and fundamental mechanistic understanding. This review provides a comprehensive and critical analysis of recent breakthroughs in the field of SACs for CO₂RR. We first delve into advanced synthetic strategies, including wet-chemistry methods, high-temperature pyrolysis, and atomic layer deposition, with a focus on the principles governing the formation and stabilization of isolated atomic sites. Subsequently, we survey the electrochemical frontiers, systematically evaluating the performance of state-of-the-art SACs for the selective production of key products such as carbon monoxide (CO), formate (HCOOH), and multicarbon (C2 +) compounds. A central theme of this review is the elucidation of structure-performance relationships, where we connect synthetic control over the catalyst's atomic and electronic structure with its resulting electrochemical behavior, highlighting insights gained from a powerful combination of operando spectroscopic techniques and density functional theory (DFT) calculations. Finally, we address the overarching challenges that currently impede the practical application of SACs—notably issues of stability, scalability, and performance in industrial-relevant devices—and offer a forward-looking perspective on the future research directions poised to overcome these hurdles, including the design of multi-atom active sites and the integration of artificial intelligence in catalyst discovery.