Local Heating Induced Single‐Crystalline Phase Control in Electrochemical Synthesis of Nanomaterials

Development of synthetic strategies selectively yielding single crystals is desired owing to the facet‐dependent chemical reactivities. Recent advances in electrochemical materials synthesis yielded nanomaterials that are surfactant‐free, however, typically in polycrystalline forms. In this work, an electrochemical synthetic strategy selectively yielding single‐crystalline nanoparticles by implementation of surface‐selective heating of the working electrode is developed. Single crystals of copper, silver, gold, and platinum are afforded, and the crystallinity verified by electron diffraction and chemical reactivity studies. Notably, Cu (100) surface prepared by electrochemical synthesis yielded high single product selectivity when applied to electrochemical CO 2 reduction catalysis.