High-Throughput Monitoring of Electrochemical Reactions on Single Nanoparticles via Fourier Transform Wide-Field Electrochemical Hyperspectral Imaging.

Abstract

High throughput, wide-field hyperspectral imaging of the dynamic and spatially inhomogeneous electrochemical interface is vital for understanding and controlling electrochemical processes. However, acquiring three-dimensional data cubes with spatial and spectral information is typically time-consuming due to the limited speed of raster scanning or wavelength tuning, which impedes fast tracking of dynamic and inhomogeneous electrochemical reactions. Here, we develop Fourier transform wide-field electrochemical hyperspectral imaging (FT-WEHI) and showcase its application to <i>in situ</i> monitor the electrodeposition of Pt on hundreds of single Au nanospheres and nanorods with detailed scattering spectra. This provides an optical analog of voltammetry for all nanoparticles simultaneously, yielding statistically meaningful results that are difficult to obtain from conventional, time-consuming single-particle studies. Statistical analysis shows that even though structural heterogeneity exists for each nanoparticle, the preferential deposition at the tips of nanorods, having relatively "homogenous" morphology and thus nucleation energy, leads to a narrower distribution of onset deposition potential compared to nanospheres. Spectral evolution reveals distinct deposition processes on nanospheres and nanorods as rationalized by simulations. Our method provides large data sets with high throughput, holding potential for accelerating the study of various energy and biological processes with data-driven strategies.