Work

Determining the State of a Pd/γ-Al2O3 Catalyst Using Pulsed Flow and Transient Spectroscopy

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide A precise understanding of heterogeneous catalyst structure and activity is required to design more efficient, greener, industrial chemical processes. While it is possible to resolve both the structure and activity of a catalyst, their innate complexity means it is nontrivial to unambiguously assign one to the other. Herein, we demonstrate how transient measurements, coupled with kinetic modeling, can be used to resolve kinetics with sufficient precision such that it is possible to resolve the identity of an “active site” over technical catalysts. We find that under CO rich conditions the transient activity and coverage dependencies measured over a Pd/γ-Al 2 O 3 catalyst during pulsed flow and transient spectroscopy CO oxidation experiments can be quantitatively predicted using a kinetic model derived from ultrahigh vacuum surface science experiments over Pd(111) single crystals. Thus, we conclude that the state (i.e., structure and composition of the active site) of the Pd/γ-Al 2 O 3 catalyst under reaction conditions is equivalent to that of a Pd(111) surface. Instead of determining a catalyst’s structure and assigning it to activity, we instead propose a new approach: using precise kinetic measurements to infer the catalyst’s state. This approach enables the identification of active sites that have been challenging to resolve using traditional spectroscopic or microscopic methods, offering a powerful and complementary tool for designing new catalysts.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c10235

Authors: Christopher R. O’Connor, Eric A. High, Taek-Seung Kim, Audrey Dannar, Christian Reece

Institutions: Harvard University, Rowland Institute at Harvard, Tufts University, Kyungpook National University

Language: English

Topic: Catalytic Processes in Materials Science

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500

Funder: Rowland Institute at Harvard