Abstract
Our sustainable future requires finding new, affordable and green routes to prepare nanostructured materials used in renewable energy conversion. In this work we present an electrodeposition method in a deep eutectic solvent (DES) to prepare bimetallic high surface area nanostructures of Cu and Au with tunable structure and composition. The metal electrodeposition performed in choline chloride within a urea deep eutectic solvent allows us to tailor the size, morphology and elemental composition of the deposits. We combine electrochemical methods with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS) to characterize the electrodeposited nanostructured materials. We assess the increase of the electroactive surface area through the analysis of the lead underpotential deposition (UPD) on the prepared films. Integrated Pb UPD charge values of ca. 1600–4000 μC/cm2 for the prepared Cu-Au films have been calculated, suggesting a 5–14 fold increase of the active surface area compared to flat surfaces of polycrystalline Cu or Au. Our work reports a versatile and environmentally friendly route for the electrodeposition of Cu-Au bimetallic nanostructures in a DES. The combination of a tailored morphology and composition with the high active surface area of the nanostructured materials show that electrodeposition in DES is promising for the development of multimetallic electrocatalysts.
Highlights
As society continues to move towards a carbon-free economy, there is an increase in the urgent demand to produce more efficient nanotechnologies for clean energy conversion [1,2]
The Cyclic voltammograms (CVs) as well as the recorded chronoamperometric transients appears in Fig. S1 of the supporting information (S.I.), with our results being in line with previous reports [23,24]
Flower-shaped gold nanoparticles (NPs) with a diameter of ca. 300 nm are formed. This morphology is likely induced by the particle agglomeration promoted by a high surface diffusion on the glassy carbon (GC) substrate
Summary
As society continues to move towards a carbon-free economy, there is an increase in the urgent demand to produce more efficient nanotechnologies for clean energy conversion [1,2]. In addition to the improved catalytic properties when combining two or more metals, nanostructured substrates usually display enhanced electrocatalytic activities (per mass unity of catalyst) compared to flat or bulk electrodes [47,48]. This is, among other reasons, because of their high electrochemically active surface area (ECSA), which accounts for the total number of reaction sites versus geometric area of the surface catalyst [49,50,51,52]. Pb UPD on metallic surfaces is a surface process sensitive to the structure and area of the catalyst which allows for a more reliable quantification of the electroactive surface area [55]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
