Tailoring the Dispersion of Metals on ZnO with Preadsorbed Water

The dispersity of metal particles over oxide surfaces is generally critical for the applications of the metal/oxide hybridized systems. In this work, we have experimentally investigated the hydration effect of preadsorbed water species over the Cu and Pd particles deposited on the ZnO(10-10) surface. Using scanning tunneling microscopy (STM), we clearly saw that both Cu and Pd grow as threedimensional particles on the clean ZnO(10-10) surface but disperse into single atoms and few-atom clusters on the water-covered surfaces. Moreover, X-ray photoelectron spectroscopy (XPS) measurements revealed that Cu is readily oxidized by interacting with the molecular water while Pd tends to bind the surface hydroxyls and keep neutral status. Our work has demonstrated the effective role of the surface water in tuning the morphologies as well as electronic states of the supported metals, which may bring new insights to a number of important surface processes with water in presence.

Automated summary

This work experimentally investigated the dispersion effect of water on Cu and Pd particles deposited on the ZnO(10-10) surface. It was found that water led to the dispersion of particles into single atoms and few-atom clusters. XPS measurements showed that Cu was easily oxidized by water, while Pd tended to bind surface hydroxyls and remain in a neutral state. These findings provide important insights into surface processes with water.