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<p>A series of bimetallic AuPd/TiO<sub>2</sub> catalysts (Au/Pd = 1) were prepared through either the impregnation or the deposition-precipitation in urea (DPU) approach and tested in the CO oxidation reaction. Among these, the sample synthesized through a sequential impregnation (Pd) followed by DPU (Au), with an intermediate thermal treatment in air, presented a remarkable CO conversion at sub-ambient temperatures and an enhanced catalytic stability, compared to the monometallic samples. The ex-situ characterization revealed that the synthesis procedure led to the formation of well-dispersed bimetallic AuPd nanoparticles over the TiO<sub>2</sub> support. The in-situ characterization helped to propose that bimetallic NPs were composed of an intermetallic Au-Pd phase with both atoms available in the surface. Both in-situ FTIR and UV-vis spectroscopies helped to recognize the active sites during the reaction: Au in close interaction with the TiO<sub>2</sub> at low temperatures, and step/edges Pd sites at high temperatures. Finally, the pivotal role of the TiO<sub>2</sub> reducibility in the CO oxidation reaction, promoted by the bimetallic AuPd NPs, was determined through in-situ Raman spectroscopy.</p>

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AuPd/TiO2 Catalysts in the CO Oxidation: Insights into the Synthesis Procedure and In-situ Spectroscopy Studies

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年1月27日

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  • Daniel G. Araiza,
  • Misael Fernández,
  • Mariana Sánchez-Ugalde,
  • Aida Miranda,
  • Dora A. Solís-Casados,
  • Viridiana Maturano-Rojas,
  • Rodolfo Zanella

摘要

A series of bimetallic AuPd/TiO2 catalysts (Au/Pd = 1) were prepared through either the impregnation or the deposition-precipitation in urea (DPU) approach and tested in the CO oxidation reaction. Among these, the sample synthesized through a sequential impregnation (Pd) followed by DPU (Au), with an intermediate thermal treatment in air, presented a remarkable CO conversion at sub-ambient temperatures and an enhanced catalytic stability, compared to the monometallic samples. The ex-situ characterization revealed that the synthesis procedure led to the formation of well-dispersed bimetallic AuPd nanoparticles over the TiO2 support. The in-situ characterization helped to propose that bimetallic NPs were composed of an intermetallic Au-Pd phase with both atoms available in the surface. Both in-situ FTIR and UV-vis spectroscopies helped to recognize the active sites during the reaction: Au in close interaction with the TiO2 at low temperatures, and step/edges Pd sites at high temperatures. Finally, the pivotal role of the TiO2 reducibility in the CO oxidation reaction, promoted by the bimetallic AuPd NPs, was determined through in-situ Raman spectroscopy.