Facet-controlled electrosynthesis of nanoparticles by combinatorial screening in scanning electrochemical cell microscopy†

Abstract

Controlled synthesis of faceted nanoparticles on surfaces without explicit use of ligands has gained attention due to their promising applications in electrocatalysis and chemical sensing. Electrodeposition is a desirable method; however, precise control over their size, spatial distribution, and morphology requires extensive optimization. Here, we report the spatially resolved synthesis of shape-controlled Pt nanoparticles and fast screening of synthesis conditions in scanning electrochemical cell microscopy (SECCM) with pulse potentials. The screening is performed on isolated ∼μm² areas in SECCM, enabling multiple experimental conditions to be evaluated in a single mapping experiment. The screening reveals that the formation of (100) facets in Pt nanoparticles is sensitive to the upper and lower potential limits of the square-wave potential pulse. The facet selectivity is attributed to a facet-dependent migration effect influenced by the concurrent hydrogen evolution reaction during Pt deposition. Moreover, the density and size of nanoparticles can be controlled. This approach offers a pathway toward automated synthesis and characterization of faceted metallic nanoparticles, providing opportunities for advancements in electrocatalysis and sensor development.