# Operando X‐ray Spectroscopy Study of Pd and Pd–Au Laterally Condensed Catalysts during Selective Acetylene Hydrogenation: The Role of Carbon

## TL;DR

This study uses X-ray techniques to explore how carbon affects the performance of Pd and Pd–Au catalysts in acetylene hydrogenation.

## Contribution

The study reveals that Pd catalysts incorporate more carbon than Pd–Au ones, which significantly impacts their catalytic activity.

## Key findings

- Pd can incorporate more carbon into its lattice than Pd–Au, affecting catalytic activity.
- Carbon uptake influences the chemical and electronic structure of the catalysts during reactions.
- Operando spectroscopy tracks carbon's role in the hydrogenation process.

## Abstract

In this study, near ambient pressure X‐ray photoelectron and X‐ray absorption spectroscopy (NAP‐XPS and NAP‐XAS) were performed during the selective acetylene hydrogenation reaction on Pd and Pd‐Au laterally condensed catalysts. The activity and selectivity of this reaction are strongly influenced by the incorporation of carbon into the Pd and Pd–Au lattice, which is investigated by both experiment and theory. We find that Pd can take up much more carbon than Pd‐Au, which can be used to tune the activity of the catalyst during the hydrogenation reactions. The amount of the carbonaceous species dissolved in the Pd and Pd–Au lattice was quantified and their effect on the chemical and the electronic structure was tracked by means of operando spectroscopy throughout different stages of the acetylene hydrogenation reaction.

The selective hydrogenation of acetylene over laterally condensed Pd and Pd–Au catalysts (LCCs) was investigated using operando X‐ray absorption and photoelectron spectroscopy in combination with density functional theory. Pd‐LCCs were found to incorporate significantly more carbon into the metal lattice than Pd–Au LCCs, where the carbon uptake governs the evolution of their chemical and electronic structure, exerting a pronounced influence on catalytic activity.