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Vibrationally Excited CO2 Formed in CO + NO Reaction on Pd(110) Surface in High Surface Temperature Range

“…Hence, a fundamental understanding of the reaction mechanism of the CO+NO reaction on Pd surfaces is of vital importance. Many ultra high vacuum (UHV) studies have focused on the nature of CO and NO chemisorption on single-crystal Pd surfaces [2][3][4][5], however, only a few groups have studied the steady-state CO+NO reaction over well-defined surfaces [6][7][8][9][10]. The utilization of single crystal surfaces can be useful for the elucidation of the reaction mechanism over heterogeneous catalysts.…”

“…The utilization of single crystal surfaces can be useful for the elucidation of the reaction mechanism over heterogeneous catalysts. An effective method is an investigation of internal (vibrational and rotational) energy and translational energy of product molecules desorbed from the catalyst surface [8][9][10][11][12][13][14][15]. This is because the energy states of desorbed molecules can reflect the dynamics of catalytic reaction, which correspond to a transition state (i.e., structure of activated complex).…”

“…Analysis of the vibrational states can give the information on the structure of the activated CO 2 complex (i.e., the dynamics of CO oxidation) from which the gas phase molecules are desorbed [11,[13][14][15]. Furthermore, the vibrational energy state of the product CO 2 has been found to depend on the surface structure [10,11]. So, information about the active sites can be obtained in situ from the IR emission spectra of CO 2 under steady-state catalytic reaction.…”

“…Our group has reported IR chemiluminescence of CO 2 from the steady-state CO+O 2 and CO+NO reactions on single crystal Pd surfaces combined with kinetic results [10,11]. In the temperature range of 620-720 K, the average vibrational temperature of CO 2 from CO+NO reaction was almost the same as that from CO+O 2 reaction on both Pd(110) and Pd(111), and the vibrational temperature on Pd(111) was higher than that on Pd(110).…”

“…In the temperature range of 620-720 K, the average vibrational temperature of CO 2 from CO+NO reaction was almost the same as that from CO+O 2 reaction on both Pd(110) and Pd(111), and the vibrational temperature on Pd(111) was higher than that on Pd(110). Since the emission intensity analysis of the spectra can give the antisymmetric vibrational temperature and it is possible to estimate the bending vibrational temperature at the same time, we can discuss the structure of activated complex of CO 2 formation from the comparison between these two vibrational temperatures, although the details were not reported in our previous paper [10].…”