Controlled formation of shape structures via electrochemical surface modification of Cu(111)

• The structure of a Cu(111) single crystalline electrode has been electrochemically reconstructed with chloride and by using a square-wave potential signal. • Applying potential pulses between −1.3 v and 0.5 v vs SCE and with a frequency of 1 hz produced tetrahexahedral copper clusters embedded in a (111) surface at the early stages of the deposition process. • The shape of the embedded tetrahexahedral clusters changed with time, transitioning from hexagonal to triangular pyramidal shape. • This work demonstrates the applicability of the square-wave potential method for controlled deposition of high-index (n10) copper shape structures onto copper. Electrochemical oxidation-reduction processes on copper electrodes and in the presence of different electrolyte anions have been widely explored for the preparation of tailor-made catalysts. Nevertheless, the effect of the electrode surface structure and electrolyte on the growth of new crystalline domains on copper remains under discussion. In this work, we have modified a Cu(111) single crystalline electrode with chloride by using the square-wave potential method, aiming to reach a higher control on the formation of shape structures. In particular, we have modified the single-facet surface by applying potential pulses with a frequency of 1 Hz and between -1.3 V and 0.5 V vs SCE. Then, we evaluated the formation of new structures with scanning electron microscopy after different times of applied potential pulses. The morphology analysis revealed the formation of hexagonal micro and nanoclusters homogeneously distributed on the surface. These clusters were similar to tetrahexahedral particles embedded in the (111) plane. Moreover, we also observed a shape transformation from a hexagonal particle to a triangular pyramid, showing that crystal growth and evolution are time and structure dependent. Herein, we provide experimental insights on the preparation of (n10) micro and nanostructures of copper using the square-wave potential method. The present work offers a straightforward approach that enables precise control over the rational preparation of copper surfaces. Here we modify a well-defined Cu(111) electrode using chloride and the square-wave potential method for controlled formation of (n10) shape nano and micro structures on copper.