Observing atomic layer electrodeposition on single nanocrystals surface by dark field spectroscopy

Shu Hu,Jun Yi,Bi-Ju Liu,Kai-Qiang Lin,Bin Ren,Yue-Jiao Zhang,Jian-Feng Li,Cheng Zong,Zhi-Chao Lei,Liang Chen,Juan-Juan Sun,Chao Zhan

doi:10.1038/s41467-020-16405-3

Abstract

Underpotential deposition offers a predominant way to tailor the electronic structure of the catalytic surface at the atomic level, which is key to engineering materials with a high activity for (electro)catalysis. However, it remains challenging to precisely control and directly probe the underpotential deposition of a (sub)monolayer of atoms on nanoparticle surfaces. In this work, we in situ observe silver electrodeposited on gold nanocrystals surface from sub-monolayer to one monolayer by designing a highly sensitive electrochemical dark field scattering setup. The spectral variation is used to reconstruct the optical “cyclic voltammogram” of every single nanocrystal for understanding the underpotential deposition process on nanocrystals, which cannot be achieved by any other methods but are essential for creating novel nanomaterials.

Highlights

Underpotential deposition offers a predominant way to tailor the electronic structure of the catalytic surface at the atomic level, which is key to engineering materials with a high activity forcatalysis
The sensitivity of the electrochemical dark field scattering (EC-DFS) technique can be dramatically improved
Such a great improvement enables the detection of the spherical Au NPs with a diameter as low as 10–15 nm without using a special light source or equipment, as we demonstrated in Supplementary Fig. 3

Summary

Introduction

Underpotential deposition offers a predominant way to tailor the electronic structure of the catalytic surface at the atomic level, which is key to engineering materials with a high activity for (electro)catalysis. It remains challenging to precisely control and directly probe the underpotential deposition of a (sub)monolayer of atoms on nanoparticle surfaces. The spectral variation is used to reconstruct the optical “cyclic voltammogram” of every single nanocrystal for understanding the underpotential deposition process on nanocrystals, which cannot be achieved by any other methods but are essential for creating novel nanomaterials. We develop a highly sensitive electrochemical dark field scattering (EC-DFS) setup for in situ monitoring the UPD process of Ag on Au nanocrystals (NCs). It enables identification of small spectral variations induced by the deposition of submonolayer atoms in the electrochemical environment. This work provides unprecedented information for understanding the UPD process on NCs, and allows the control of the UPD process at the single NP level that are of both fundamental and technological importance for electrocatalysis

Methods

Results

Conclusion