Orbital Matching Mechanism-Guided Synthesis of Cu-Based Single Atom Alloys for Acidic CO₂ Electroreduction

Recent advancements in alloy catalysis have yield novel materials with tailored functionalities. Among these, Cu-based single-atom alloy (SAA) catalysts have attracted significant attention in catalytic applications for their unique electronic structure and geometric ensemble effects. However, selecting alloying atoms with robust dispersion stability on the Cu substrate is challenging, and has mostly been practiced empirically. The fundamental bottleneck is that the microscopic mechanism that governs the dispersion stability is unclear, and a comprehensive approach for designing Cu-based SAA systems with simultaneous dispersion stability and high catalytic activity is still missing. Here, combining theory and experiment, a simple yet intuitive d-p orbital matching mechanism is discovered for rapid assessment of the atomic dispersion stability of Cu-based SAAs, exhibiting its universality and extensibility for screening effective SAAs across binary, ternary and multivariant systems. The catalytic selectivity of the newly designed SAAs is demonstrated in a prototype reaction-acidic CO₂ electroreduction, where all SAAs achieve single-carbon product selectivity exceeding 70%, with Sb₁Cu reaching a peak CO faradaic efficiency of 99.73 ± 2.5% at 200 mA cm^-2. This work establishes the fundamental design principles for Cu-based SAAs with excellent dispersion stability and selectivity, and will boost the development of ultrahigh-performance SAAs for advanced applications such as electrocatalysis.