The reversible adsorption of CO₂-derived species to graphene quantum dots in CO₂ electroreduction reaction was characterized by nuclear spin hyperpolarized NMR. Hyperpolarization of ¹³C-labeled sodium bicarbonate by the dissolution dynamic nuclear polarization (DNP) technique provided a 5000-fold signal enhancement and enabled real-time and in-situ ¹³C NMR experiments. The R₁ and R₂ relaxation rates were measured using time-resolved DNP-NMR experiments, and the bound species were confirmed to be carbonic acid and its conjugates. A significant difference in the relaxation rates of bound and free species was found, indicating a reversible binding. In addition to relaxation rates, kinetic rate constants were fitted from the small-flip angle experiments and compared to theoretical calculations. The pH-dependent adsorption and desorption rate constants were found in the range of 3.5–9.5 and 0.7–2.0 s⁻¹, with the average binding distance at 279 - 291 pm. The DNP-NMR technique was demonstrated as an effective way to study surface adsorption, with potential in electrochemistry and kinetics applications.

通过核自旋超极化NMR表征了CO 2 电还原反应_{中CO 2}衍生物质对石墨烯量子点的可逆吸附。^{通过溶解动态核极化 (DNP) 技术对13} C 标记的碳酸氢钠进行超极化，信号增强了 5000 倍，并实现了实时原位¹³ C NMR 实验。R ₁和R ₂ _使用时间分辨 DNP-NMR 实验测量弛豫率，并确认结合的物质是碳酸及其缀合物。发现结合物质和游离物质的弛豫率存在显着差异，表明结合是可逆的。除了弛豫率之外，还根据小翻转角实验拟合了动力学速率常数，并与理论计算进行了比较。pH依赖性吸附和解吸速率常数在3.5-9.5和0.7-2.0 s ^-1范围内，平均结合距离在279 - 291 pm。DNP-NMR 技术被证明是研究表面吸附的有效方法，在电化学和动力学应用中具有潜力。