# Evaluating Palladium 4d-to-2p X‑ray Emission Spectroscopy for Characterizing Catalytically Relevant Species

## TL;DR

This paper explores using a specific X-ray technique to better understand palladium catalysts in chemical reactions.

## Contribution

The study introduces Pd 4d-to-2p XES as a novel method for characterizing palladium species in catalysis.

## Key findings

- Pd 4d-to-2p XES provides clearer electronic structure information for palladium compared to traditional XAS.
- The technique is effective for both homogeneous and heterogeneous palladium systems relevant to catalysis.

## Abstract

X-ray absorption spectroscopy (XAS) has diverse applications
in
materials characterization and catalysis. While K-edge XAS can provide
detailed information about electronic and geometric structures for
3d transition metals, its application to second- and third-row transition
metals is often limited by substantial core–hole lifetime broadenings.
For the later transition metals, higher d-electron counts further
reduce the electronic structural information content due to weak and
absent 1s-to-nd pre-edge features. L-shell X-ray emission spectroscopy
(XES), specifically 4d-to-2p XES, can overcome these limitations by
accessing transitions that are dipole allowed and have intrinsically
narrower core–hole lifetime broadenings. Herein, the utility
of Pd 4d-to-2p XES for in situ catalysis research in both homogeneous
and heterogeneous systems is explored through the study of well-defined
PdO
x
H
y
complexes
and Pd nanoparticles that are relevant to Pd-based catalysts.