# Design of High-Surface-Area Bimetallic Ag–Cu Nanostructures with a Tunable Ratio Obtained via Selective Leaching of AlAgCu Alloys

## TL;DR

Scientists created a new method to make nanostructured Ag-Cu metals with tunable ratios, useful for CO2 reduction catalysis.

## Contribution

A novel synthesis route for high-surface-area bimetallic Ag-Cu nanostructures with tunable Ag:Cu ratios and suppressed side phases.

## Key findings

- AgCu samples with tunable Ag:Cu ratios and nanoscale mixing were successfully synthesized.
- Catalytic tests showed optimal C2H4 production at 50–70 atom% Cu.
- The Ag:Cu molar ratios remained stable after electrochemical CO2 reduction, indicating catalyst durability.

## Abstract

Nanostructured metals are promising for applications
as energy
materials. Often, several metal components must be combined to obtain
the desired properties. However, preparing high-surface-area bimetallic
metals with a desired spatial distribution can be challenging. We
developed a novel synthesis route to make nanostructured Ag
x
Cu10‑x with control over the Ag:Cu
molar ratio, covering the full range from x = 0 to x = 10. We used a dealloying synthesis route based on leaching
Al from an AlAgCu mixed phase. We introduced a quenching step after
alloying and before leaching to suppress the formation of side phases,
which is beneficial for the leaching step. High-surface-area AgCu
samples with a tunable Ag:Cu ratio and Ag and Cu mixed on tens of
nanometer scale were obtained. The AgCu samples were applied as catalysts
in the electrochemical reduction of CO2, showing a clear
dependence of the selectivity on the Cu content. An optimum in C2H4 production was found for a Cu content between
50 and 70 atom % in the nanostructures. After catalysis, the molar
ratios had not changed significantly, showing the stability of these
catalysts. This work shows the usefulness of a method to prepare nanostructured
catalyst covering the full Ag:Cu ratio.