Wang Lu-Xuan, Zhang Miao, Sun Chao, Yin Li-Xin, Kang Bin, Xu Jing-Juan, Chen Hong-Yuan
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
Angew Chem Int Ed Engl. 2022 Mar 14;61(12):e202117177. doi: 10.1002/anie.202117177. Epub 2022 Feb 1.
Single-nanoparticle electrochemistry offers electrochemical behaviors of individual entities beyond the ensemble system. An electric double layer (EDL) exists on any charged particle-liquid interface because of counter-ion accumulation, while direct measuring of the interfacial ion migration remains a challenge. Herein, a plasmonic-based transient microscopic method, with a temporal resolution of 1-2 μs, was demonstrated to directly track the ion migration dynamics on single charged nanoparticles. We found that the dynamics of EDL formation might deviate significantly from the prediction made by using the classical resistance-capacitance (RC) model under nanoscale and transient conditions. Under ultrafast charging, due to the limit migration rate of ions in the solution, the actual time scale of the EDL formation could be up to 5 times slower than the predicted value from the RC model. We then proposed a new theoretical model to describe the transient dynamics of EDL formation. These results may expand our current knowledge about nano-electrochemistry and transient electrochemistry.
单纳米颗粒电化学能够展现单个实体在整体系统之外的电化学行为。由于反离子积累，在任何带电粒子 - 液体界面都会存在一个双电层（EDL），然而直接测量界面离子迁移仍然是一个挑战。在此，一种基于等离子体的瞬态显微镜方法被证明能够以1 - 2微秒的时间分辨率直接追踪单个带电纳米颗粒上的离子迁移动力学。我们发现，在纳米尺度和瞬态条件下，双电层形成的动力学可能会显著偏离使用经典电阻 - 电容（RC）模型所做的预测。在超快充电情况下，由于溶液中离子的迁移速率有限，双电层形成的实际时间尺度可能比RC模型预测的值慢高达5倍。然后我们提出了一个新的理论模型来描述双电层形成的瞬态动力学。这些结果可能会扩展我们目前关于纳米电化学和瞬态电化学的知识。
