Single-atom catalysts supported on solid substrates have inspired extensive interest, but the rational design of high-efficiency single-atom catalysts is still plagued by ambiguous structure determination of active sites and its local support effect. Here, we report hybrid single-atom catalysts by an axial coordination linkage of molecular cobalt phthalocyanine with carbon nanotubes for selective oxygen reduction reaction by screening from a series of metal phthalocyanines via preferential density-functional theory calculations. Different from conventional heterogeneous single-atom catalysts, the hybrid single-atom catalysts are proven to facilitate rational screening of target catalysts as well as understanding of its underlying oxygen reduction reaction mechanism due to its well-defined active site structure and clear coordination linkage in the hybrid single-atom catalysts. Consequently, the optimized Co hybrid single-atom catalysts exhibit improved 2e⁻ oxygen reduction reaction performance compared to the corresponding homogeneous molecular catalyst in terms of activity and selectivity. When prepared as an air cathode in an air-breathing flow cell device, the optimized hybrid catalysts enable the oxygen reduction reaction at 300 mA cm⁻² exhibiting a stable Faradaic efficiency exceeding 90% for 25 h.

固体载体上负载的单原子催化剂引起了广泛的兴趣，但高效单原子催化剂的合理设计仍然受到活性位点及其局部负载效应的模糊结构确定的困扰。在这里，我们通过优先密度泛函理论计算从一系列金属酞菁中筛选，报告了通过分子钴酞菁与碳纳米管的轴向配位键的混合单原子催化剂用于选择性氧还原反应。不同于传统的多相单原子催化剂，由于杂化单原子催化剂中明确的活性位点结构和清晰的配位键，杂化单原子催化剂被证明有助于合理筛选目标催化剂以及了解其潜在的氧还原反应机制。因此，优化的 Co 杂化单原子催化剂表现出改进的 2e⁻在活性和选择性方面与相应的均相分子催化剂相比的氧还原反应性能。当在吸气式流动电池装置中作为空气阴极制备时，优化的混合催化剂能够在 300 mA cm ^-2下进行氧还原反应，并在 25 小时内表现出超过 90% 的稳定法拉第效率。