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Dynamics of palladium single-atoms on graphitic carbon nitride during ethylene hydrogenation

DOI: 10.1016/j.jcat.2023.03.011 DOI Help

Authors: Maurice Vennewald (RWTH Aachen University) , Nina Michelle Sackers (RWTH Aachen University) , Andree Iemhoff (RWTH Aachen University) , Isabella Kappel (Max-Planck-Institut für Kohlenforschung) , Claudia Weidenthaler (Max-Planck-Institut für Kohlenforschung) , Ansgar Meise (Forschungszentrum Jülich GmbH) , Marc Heggen (Forschungszentrum Jülich GmbH) , Rafal E. Dunin-Borkowski (Forschungszentrum Jülich GmbH) , Luke Keenan (Diamond Light Source) , Regina Palkovits (RWTH Aachen University; Max-Planck-Institute for Chemical Energy Conversion)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Catalysis , VOL 118

State: Published (Approved)
Published: March 2023
Diamond Proposal Number(s): 29667

Abstract: Single-atoms on carbon-nitrogen supports are considered catalysts for a multitude of reactions. However, doubts remain whether really these species or subnanometer clusters formed under reaction conditions are the active species. In this work, we investigate the dynamics of palladium single-atoms on graphitic carbon nitride during ethylene hydrogenation and H2-D2 exchange. By employing aberration-corrected scanning transmission electron microscopy, x-ray photoelectron spectroscopy and x-ray absorption spectroscopy, we will show that palladium, originally present as single-atoms, agglomerates to clusters at 100 °C in a gas atmosphere that contains both ethylene and hydrogen. This agglomeration goes in hand with the emergence of catalytic activity in both ethylene hydrogenation and H2-D2 exchange, suggesting that clusters, rather than single-atoms, are the active species. The results presented herein highlight the potential of analytics over the course of reaction to identify the active species and provide new insights into the influence of gas atmosphere on metal speciation.

Subject Areas: Chemistry

Instruments: I20-EDE-Energy Dispersive EXAFS (EDE)

Added On: 13/03/2023 09:40

Discipline Tags:

Physical Chemistry Catalysis Chemistry Chemical Engineering Engineering & Technology

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)