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Site-Selective Oxide Rearrangement in a Tandem Metal–Metal Oxide Catalyst Improves Selectivity in Oxidative Dehydrogenation of Propane

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Tandem metal–metal oxide catalysts, where metallic and metal oxide active sites work synergistically to drive complex chemistries, have been shown to improve the catalyst stability, activity, and selectivity. Although experimental techniques have probed the active site structure of such catalysts, the key atomic features that drive structure evolution under synthesis and reaction conditions remain poorly understood. Here, we develop a computational framework to elucidate the chemical, geometric, and stoichiometric features of the tandem overcoated catalyst, Pt-InO x H y, in driving the Oxidative Propane Dehydrogenation (ODHP) reaction, integrating propane dehydrogenation (PDH) and Selective Hydrogen Combustion (SHC). Exploration of the chemical space of stable InO x H y phases on Pt relevant to the experimental conditions reveals that the pore formation of the ALD-deposited InO x H y catalyst results from the oxide destabilization on well-coordinated Pt-terrace sites and preferential decoration around under-coordinated Pt-step sites. Reaction mechanistic analysis of the Pt-InO x H y catalyst reveals a dual-site mechanism for SHC, where O* activates on Pt and subsequently forms OH* at the InO x H y sites, facilitating water formation and controlling overoxidation. Further, due to passivation of the under-coordinated Pt-step sites, the Pt-InO x H y surface exhibits similar PDH activity as that on a well-coordinated Pt-terrace surface, in addition to enhanced stability by destabilizing deep-dehydrogenated intermediates. These insights establish a structure–performance relationship of the Pt-InO x H y catalyst for ODHP chemistry, with key features being the extent of reducibility of the metal oxide and the sensitivity of the oxide structure to the oxygen chemical potential. This framework can be extended to other metal–metal oxide systems and complex reactions to develop next-generation tandem catalysts.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c13571

Authors: Snehitha Srirangam, Siddharth Deshpande

Institution: University of Rochester

Language: English

Topic: Catalysis and Oxidation Reactions

Subfield: Catalysis

Field: Chemical Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funders: National Science Foundation, University of Rochester, Centre International de Recherche sur le Cancer, Office of Advanced Cyberinfrastructure