Single atoms confined in crystalline porous materials such as metal–organic frameworks (MOFs) feature unparallel multidimensional interactions with the molecular wall of nano-cavities, showcasing a synergistic catalytic effect. Nevertheless, the insulating nature and long yet narrow diffusion channels of MOFs render most single-atom mass/electrons inaccessible, resulting in an exceedingly low single-atom utilization efficiency. Herein, we propose downsizing MOF particles into quantum dots (QDs) to shorten the mass transfer route and amplify interfacial electron transfer. As a proof of concept, base-resistant MOF QDs with isolated Co atoms (PCN-QDs, ∼1.5 nm) were constructed for CO₂ electroreduction. A reduction in diffusion time by five orders of magnitude was realized compared to pristine MOF particles. A strong MOF QD-support electronic interaction was confirmed, which not only expedited interfacial electron transfer but also introduced electronic regulation in the Co atoms. Theoretical calculations showed greater electron accumulation on the Co atom and an up-shifted d-band center, resulting in a moderate adsorption strength for *COOH and *CO. Eventually, the PCN-QD delivered a record high single-atom utilization efficiency of 93.0% and manifested an FE_CO higher than 90.0% within the range of −0.13 to −1.05 V, even under an ampere-level current density (−0.95 A cm⁻²).

中文翻译：

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用于安培级 CO2 电还原的耐碱金属有机框架量子点单原子利用率为 93%

限制在金属有机框架（MOF）等结晶多孔材料中的单原子具有与纳米腔分子壁无与伦比的多维相互作用，表现出协同催化效应。然而，MOFs的绝缘性和又长又窄的扩散通道使得大多数单原子质量/电子难以接近，导致单原子利用效率极低。在此，我们建议将 MOF 颗粒缩小为量子点（QD），以缩短传质路径并增强界面电子转移。作为概念验证，构建了具有孤立 Co 原子的耐碱 MOF QD（PCN-QD，~1.5 nm）用于 CO ₂电还原。与原始 MOF 颗粒相比，扩散时间减少了五个数量级。证实了 MOF QD 支持的强电子相互作用，这不仅加速了界面电子转移，而且在 Co 原子中引入了电子调节。理论计算表明，Co 原子上有更多的电子积累，并且 d 带中心上移，导致 *COOH 和 *CO 具有中等的吸附强度。最终，即使在安培级电流密度（-0.95 A）下，PCN-QD 也实现了创纪录的高单原子利用率 93.0%，并在 -0.13 至 -1.05 V 范围内表现出高于 90.0% 的FE _CO厘米^-2）。