In Situ Spectroscopy and Microscopy Insights into the CO Oxidation Mechanism on Au/CeO2(111)

• DOI: 10.1021/acsami.2c15792
• Publication Date: 2022-12-09T09:50:58Z
• Authors: Lesia Piliai; Peter Matvija; Thu Ngan Dinhová; Ivan Khalakhan; Tomas Skála; Zdeněk Doležal; Oleksii Bezkrovnyi; Leszek Kepinski; Mykhailo Vorokhta; Iva Matolínová
• Keywords: 0103 physical sciences; 01 natural sciences; 0104 chemical sciences

In this work, we prepared and investigated in ultra-high vacuum (UHV) two stoichiometric CeO2(111) surfaces containing low high amounts of step edges decorated with 0.05 ML gold using synchrotron-radiation photoelectron spectroscopy (SRPES) scanning tunneling microscopy (STM). The UHV study helped to solve the still unresolved puzzle on how one-monolayer-high ceria affect metal–substrate interaction between Au surface. It was found that concentration ionic Au+ species surface increases increasing number is not correlated Ce3+ ions are supposed form after its nanoparticles. We associated an additional channel formation related atoms various peroxo oxygen formed at during film growth. CO oxidation highly stepped Au/CeO2(111) model sample performed by combining near-ambient-pressure X-ray (NAP-XPS), UHV-STM, STM (NAP-STM). This powerful combination provided comprehensive information processes occurring CO, O2, + O2 (1:1) mixture conditions close real working oxidation. system demonstrates stability CO. However, undergoes substantial chemical morphological changes as added reaction cell. Already 300 K, nanoparticles begin grow a mechanism involves disintegration small favor large ones. With temperature, catalyst quickly transforms into primarily particles contains no species.