1. Abnormally narrow peaks in TPR-H2 over Pt/CeO2: Experiment and mathematical modelling.
- Author
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Lashina, Elena A., Slavinskaya, Elena M., Stonkus, Olga A., and Boronin, Andrei I.
- Subjects
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TEMPERATURE-programmed reduction , *HYDROGEN as fuel , *HETEROGENEOUS catalysts , *CERIUM oxides , *LOW temperatures , *AUTOCATALYSIS , *PLATINUM - Abstract
The application and development of methods using hydrogen as a gas for testing active surface sites is of great interest in the study of oxide catalysts. In this work a systematic study of Pt/CeO 2 catalysts, depending on the platinum loading and calcination temperature was carried out using the method of temperature-programmed reduction by hydrogen (TPR-H 2). Experimental TPR-H 2 curves demonstrated a complex structure over a wide temperature range, including the presence of abnormally narrow consumption peaks (ANCP-H 2) at low temperatures. To describe the kinetics, mathematical modeling of H 2 consumption by various platinum active centers has been used, including isolated platinum ions (single atoms) and PtO x clusters of 2D and 3D structures on the surface of ceria nanoparticles. We proposed a criterion that makes it possible to extend the analysis of the TPR-H 2 curves for reducible metal-supported oxide systems and unambiguously establish the action of the autocatalytic mechanism in hydrogen consumption. The kinetics of ANCP-H 2 by cluster PtO x centers with a half-width of several degrees on the base of the autocatalysis mechanism was described on the base of the proposed model. The simulations show that ANCP-H 2 are described by synchronous fast formation of metallic centers that provide a sharp acceleration of H 2 consumption. In general, the obtained results establish the fundamental aspects of the H 2 interaction with heterogeneous catalysts and are of particular interest in the light of various practical applications of hydrogen energy. [Display omitted] • Pt/CeO 2 catalysts were studied depending on Pt loading using TPR-H 2 method. • TPR-H 2 curves are capable to distinguish Pt2+-SA sites and PtOx cluster. • Abnormally narrow peaks (ANCP-H 2) were observed due to 2D- and 3D-PtO x clusters. • ANCP-H 2 are well simulated on the base of the autocatalytic stages of PtO x reduction. • ANCP-H 2 is due to strong difference in the oxygen reactivity of Pt–O –Pt and Pt–O–Ce. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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