Conversion of polydispersed nanoparticles to their monodispersed analogues and formation of organized superstructures using them involve post synthetic modifications and the process is generally slow. We show that ambient electrospray...

Two-dimensional nanostructures with atomically precise building blocks have potential applications in catalysis and sensing. However, structural instability and surface reactivity limit their practical use. In this work, we demonstrate the formation of vertically aligned nanoplates of the [Co6S8DPPE6Cl6] cluster (Co6 in short), protected by 1,2-bis­(diphenylphosphino)­ethane, using ambient electrospray deposition (ESD). Charged microdroplets of Co6 formed by ESD on a water surface created such nanostructures. Preferential arrangement of clusters in the nanoplates with enhanced surface area results in sensitive and selective electrochemical response toward arsenite down to 5 parts per billion, in tap water. Density functional theory calculations reveal the preferential binding of arsenite with Co6. Our work points to a practical application of atomically precise clusters of large societal relevance.

Onion-like carbons (OLCs) are a class of fullerene-like circular nanoallotropes of carbon, typically synthesized from nanodiamond (ND) via thermal annealing, plasma spraying, and laser ablation. These methods require high temperature, high vacuum, or inert gas. Here, we report an ambient electrospray deposition (AESD) process to transform NDs (11 ± 1 nm in size) into OLCs (50 ± 13 nm in size) in water. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used for the characterization of NDs and OLCs. High-resolution TEM images showed an increased interplanar spacing from ND (0.23 nm) to OLC (0.39 nm). Raman spectra showed a shift in the ND peak from 1336 cm–1 to D-band at 1349 cm–1, and XPS quantitatively estimated an increase in the graphitization ratio (sp2/sp3) from 0.95 to 3.16 after AESD. Comparison of electrospray with sonic spray confirmed that such a transformation required an external voltage as well. AESD was also performed for NDs dispersed in ethanol and acetonitrile, which showed a solvent-dependent transformation.