Electrodeposition of tuneable Cu-Ag nanostructures in a deep eutectic solvent

Abstract

The green transition requires the preparation of clean, inexpensive, and sustainable strategies to prepare controllable bimetallic and multimetallic nanostructures. Cu-Ag nanostructures, for example, are promising bimetallic catalysts for different electrocatalytic reactions such as carbon monoxide and carbon dioxide reduction. In this work, we present the one-step preparation method of electrodeposited Cu-Ag with tunable composition and morphology from choline chloride plus urea deep eutectic solvent (DES), a non-toxic and green DES. We have assessed how different electrodeposition parameters affect the morphology and composition of our nanostructures. We combine electrochemical methods with ex-situ scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) to characterize the nanostructures. We have estimated the electrochemically active surface area (ECSA) and roughness factor (R) by lead underpotential deposition (UPD). The copper/silver ratio in the electrodeposited nanostructures is highly sensitive to the applied potential, bath composition, and loading. We observed that silver-rich nanostructures were less adherent whereas the increase in copper content led to more stable and homogenous films with disperse rounded nanostructures with tiny spikes. These spikes were more stable when the deposition rate was fast enough and the molar ratio of Cu and Ag no greater than approximately two to one.

Composition effects of electrodeposited Cu-Ag nanostructured electrocatalysts for CO2 reduction

“…[44,[46][47][48][49][50] In this paper, we use our sustainable and simple method from a choline chloride urea DES to prepare electrodeposited Cu-Ag bimetallic nanostructured catalysts for CO2RR. [51] We have prepared Cu and Cu-Ag nanostructures and rationally assessed how the introduction of silver changes the product selectivity and intrinsic activity toward CO2RR. We have used two different bath compositions and prepared different loadings to evaluate how small changes in surface morphology, size of the nanostructures, and composition affect the performance.…”