Boosting the activity of PdAg2/Al2O3 supported catalysts towards the selective acetylene hydrogenation by means of CO-induced segregation: A combined NAP XPS and mass-spectrometry study

A. V. Bukhtiyarov, M. A. Panafidin, I. P. Prosvirin, I. S. Mashkovsky, P. V. Markov, A. V. Rassolov, N. S. Smirnova, G. N. Baeva, Christoph Rameshan, Raffael Rameshan, Y. V. Zubavichus, V. I. Bukhtiyarov, A. Yu Stakheev

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Abstract

Selective hydrogenation (or semi-hydrogenation) of acetylene into ethylene is an important industrial process. The aim of the present work is thus to learn regularities governing the CO-induced segregation and elaborate practical procedures for tuning the surface structure of Pd-Ag nanoparticles to improve their catalytic performance towards the selective hydrogenation of acetylene to ethylene. Utilizing NAP XPS the CO adsorption-induced Pd atoms segregation in supported PdAg2/Al2O3 catalysts already at room temperature has been shown. The surface enrichment with Pd further increases if the treatment temperature is increased up to 250 °C. This specific configuration with a redistributed Pd/Ag surface atomic ratio is appreciably stable and self-sustained even at the absence of CO at moderately elevated temperatures. Nevertheless, a reductive treatment in hydrogen at 450 °C reverts the nanoparticle surface structure to the pristine state. Catalytic properties of this peculiar CO-induced configuration of PdAg2/Al2O3 towards the selective acetylene hydrogenation was investigated using a combination of NAP XPS and MS techniques. The PdAg2/Al2O3 catalyst with the surface enriched with Pd due to the CO-induced segregation manifests improved activity with 100 % selectivity under the conditions used. The results obtained clearly demonstrate that CO adsorption-induced segregation is a powerful tool that can be used to optimize the surface composition and catalytic performance of bimetallic nanoparticles.
Original languageEnglish
Article number154497
Number of pages7
JournalApplied surface science
Volume604.2022
Issue number1 December
Early online date10 Aug 2022
DOIs
Publication statusPublished - 1 Dec 2022
Externally publishedYes

Bibliographical note

Publisher Copyright: © 2022 Elsevier B.V.

Keywords

  • Acetylene hydrogenation
  • CO adsorption-induced segregation
  • In situ measurements
  • Near-ambient pressure X-ray photoelectron spectroscopy
  • Pd-Ag bimetallic catalysts

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