Fourier transform voltammetric studies of single nanoparticles transition impacts at the micro-liquid/liquid interface

摘要

Fourier transform large-amplitude sinusoidal voltammetry (FTSV) is applied to study the single nanoparticle transition impacts at micro-liquid/liquid interface. Through short-time Fourier transform, the current response signal of platinum nanoparticles colliding on the liquid/liquid interface of micro tubes was first deducted in time domain and frequency domain, and the single-period sinusoidal voltammetry curve and the first harmonic phase angle were separated, respectively. The results show that for platinum nanoparticles with different sizes, the first harmonic phase angle of the current response signal has no obvious monotonic relationship with the particle size, but varies about & PLUSMN; 25 & DEG; with the difference of the particle zeta potential. Then, platinum and gold nanoparticles with similar size were studied simultaneously, and the first harmonic phase angles of their collision signals were distributed in different regions, which can be identified and detected. The further studies reveal that the mechanism was root in their different permittivity. This work solves the problem of low signal-to-noise ratio within the potential window by applying a potential with large amplitude, and tries to find out the relationship between electrochemical responses and the electrostatic properties of single nanoparticles by single transition impacts. This study has a promising application in the establishment of a highly sensitive and selective electrochemical analysis method based on the liquid/liquid interface.

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