# Mechanistic Insights of Support Dynamics During Reactive Metal‐Support Interaction

## TL;DR

This study uses advanced microscopy to reveal how PdO nanoparticles on ZnO form ZnPd during reduction, providing insights into metal-support interactions in catalysts.

## Contribution

The study provides new mechanistic insights into reactive metal-support interactions through in situ environmental scanning transmission electron microscopy.

## Key findings

- Hydrogen spillover activates the ZnO support, leading to encapsulation and Zn reduction.
- Zn diffuses into the Pd lattice, forming ZnPd via interfacial, diffusion-controlled growth.
- Structural evolution during reduction reveals partial core-shell structures in the catalyst system.

## Abstract

Reactive metal‐support interactions (RMSI) are pivotal preparatory steps in the synthesis of many supported bimetallic nanoparticles. However, there is still a knowledge gap regarding the precise mechanics of such interactions, especially regarding support activation. The present study investigates the reduction of PdO nanoparticles supported on ZnO and the formation of the intermetallic compound ZnPd, using environmental scanning transmission electron microscopy (E‐STEM). The ZnO support is activated due to hydrogen spillover from the nanoparticle, which then migrates to the nanoparticle and thereby forms an encapsulation layer. Subsequently, Zn is reduced to the metallic state and diffuses into the Pd lattice at the interface, forming ZnPd and resulting in partial core‐shell structures. Structural analysis reveals that intermetallic ZnPd phase growth is diffusion‐controlled and facilitated by interfacial nucleation. These findings provide mechanistic insights into reactive metal‐support interactions, demonstrating the structural evolution of the supported catalyst system during reduction.

This study uses in situ environmental scanning transmission electron microscopy to investigate the reduction of PdO nanoparticles on ZnO and the formation of intermetallic ZnPd. Hydrogen spillover activates the ZnO support, inducing encapsulation and Zn reduction. Subsequent Zn diffusion into Pd forms ZnPd via interfacial, diffusion‐controlled growth, elucidating reactive metal–support interactions.