Adsorption and Reaction of CO and NO on Ir(111) Under Near Ambient Pressure Conditions

作者：Ueda K; Suzuki K; Toyoshima R; Monya Y; Yoshida M; Isegawa K; Amemiya K; Mase K; Mun B S; Arman M A; Granas E; Knudsen J; Schnadt J; Kondoh H^*

来源：Topics in Catalysis, 2016, 59(5-7): 487-496.

DOI：10.1007/s11244-015-0523-5

• CO adsorption
• NO adsorption
• NO plus CO reaction
• Ir(111)
• In-situ observation
• NAP-XPS

The adsorption and reaction of CO and NO on Ir(111) have been studied by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) together with low-energy electron diffraction, scanning tunneling microscopy, and mass spectroscopy (MS). Under both ultrahigh vacuum (UHV) and NAP conditions CO molecules occupy on-top sites of the Ir(111) surface at room temperature (RT) by forming two-dimensional clusters. Exposure to NO under UHV conditions at RT induces partially dissociative adsorption, while NAP NO exposure leads to a Ir(111) surface that is covered by molecular NO. We conducted in-operando NAP-XPS/MS observation of the NO + (CO)-C-13 reaction under a NAP condition as a function of temperature. Below 210 degrees C adsorption of NO is inhibited by CO, while above 210 degrees C the CO inhibition is released due to partial desorption of CO and dissociative adsorption of NO starts to occur leading to associative formation of N-2. Under the most active condition studied here the Ir surface is covered by a dense co-adsorption layer consisting of on-top CO, atomic N and O, which suggests that this reaction is not a NO-dissociation-limited process but a N-2/CO2 formation-limited process.

• 出版日期2016-3