Real-time dynamics and structures of supported subnanometer catalysts via multiscale simulations

Yifan Wang; Jake Kalscheur; Ya-Qiong Su; Emiel J M Hensen; Dionisios G Vlachos

doi:10.1038/s41467-021-25752-8

Real-time dynamics and structures of supported subnanometer catalysts via multiscale simulations

Nat Commun. 2021 Sep 14;12(1):5430. doi: 10.1038/s41467-021-25752-8.

Authors

Yifan Wang^#^{1

2}, Jake Kalscheur^#^{1

2}, Ya-Qiong Su^#^{3

4}, Emiel J M Hensen⁵, Dionisios G Vlachos^{6

7}

Affiliations

¹ Department of Chemical and Biomolecular Engineering, 150 Academy St., University of Delaware, Newark, Delaware, DE, 19716, United States.
² Catalysis Center for Energy Innovation (CCEI), RAPID Manufacturing Institute, and Delaware Energy Institute (DEI), 221 Academy St., University of Delaware, Newark, Delaware, DE, 19716, United States.
³ School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Materials Chemistry, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an, 710049, China.
⁴ Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
⁵ Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands. e.j.m.hensen@tue.nl.
⁶ Department of Chemical and Biomolecular Engineering, 150 Academy St., University of Delaware, Newark, Delaware, DE, 19716, United States. vlachos@udel.edu.
⁷ Catalysis Center for Energy Innovation (CCEI), RAPID Manufacturing Institute, and Delaware Energy Institute (DEI), 221 Academy St., University of Delaware, Newark, Delaware, DE, 19716, United States. vlachos@udel.edu.

^# Contributed equally.

Abstract

Understanding the performance of subnanometer catalysts and how catalyst treatment and exposure to spectroscopic probe molecules change the structure requires accurate structure determination under working conditions. Experiments lack simultaneous temporal and spatial resolution and could alter the structure, and similar challenges hinder first-principles calculations from answering these questions. Here, we introduce a multiscale modeling framework to follow the evolution of subnanometer clusters at experimentally relevant time scales. We demonstrate its feasibility on Pd adsorbed on CeO₂(111) at various catalyst loadings, temperatures, and exposures to CO. We show that sintering occurs in seconds even at room temperature and is mainly driven by free energy reduction. It leads to a kinetically (far from equilibrium) frozen ensemble of quasi-two-dimensional structures that CO chemisorption and infrared experiments probe. CO adsorption makes structures flatter and smaller. High temperatures drive very rapid sintering toward larger, stable/metastable equilibrium structures, where CO induces secondary structure changes only.