Adsorption Behavior and Reaction Properties of NO and CO on Ir(111) and Rh(111)

Abstract

Adsorption and reactions of NO over the clean and and Rh(111) surfaces were investigated using infrared reflection absorption spectroscopy (IRAS) and temperature programmed desorption (TPD). Two NO adsorption states, indicative of hollow and atop sites, were present on Ir(111). Only NO adsorbed on hollow sites dissociated to N a and O a . The dissociated N a desorbed as N 2 by recombination of N a and by a disproportionation reaction between atop-NO and N a . Preadsorbed CO inhibited atop-NO, whereas hollow-NO was not affected. Adsorbed CO reacted with O a and desorbed as CO 2 . NO adsorbed on the fcc-hollow, atop, and hcp-hollow sites in that order over Rh(111). The hcp-NO was inhibited by preadsorbed atop-CO, and fcc-NO and atop-NO were inhibited by CO preadsorbed on each type of the sites, indicating that NO and CO competitively adsorbed on Rh(111). From the Rh(111) surface-coadsorbed NO and CO, N 2 was produced by fcc-NO dissociation, and CO 2 was formed by reaction of adsorbed CO with O a from dissociated fcc-NO.

Reduction of NO by CO on Unsupported Ir: Bridging the Materials Gap

“…[37] NCO also forms on unsupported metals under high reaction pressures, for example, on Pd(111) under a total NO + CO pressure of at least 0.6 mbar [38] and on Ir(211) at a NO + CO pressure of 10 Torr. [39] However, such species were not found on Ir(211) [40] and Ir(111) [41] under UHV conditions. Therefore, the formation of NCO as a reaction intermediate on planar and faceted Ir(210) under our experimental condition is unlikely, that is, production of N 2 and CO 2 on planar and faceted Ir(210) in Figure 5 also occurs via NO dissociation to N and O followed by recombination and desorption of N and reaction of O with CO.…”

A high effective adsorbent of NOx: Preparation, characterization and performance of Ca-beta zeolites

“…Therefore, great efforts have been made to an efficient elimination of NOx in recent years. Up to now, the disposed methods to eliminate NOx mainly involve catalytic decomposition [3][4][5], selective non-catalytic reduction (SNCR) [6][7][8], selective catalytic reduction (SCR) [9,10], NOx storage reduction (NSR) [11] and adsorption [12,13]. As the approach of NOx adsorption at low temperature has the advantages of high efficiency, simple equipment, simple operation and easy automata [14][15][16], it can be adopted to deal with the gases including NOx with large space velocity and low concentrations; After the saturation adsorption of NOx is reached, NOx adsorbed will be desorbed and further decomposed or reduced at higher temperature.…”

Nanofaceted Metal Surfaces

“…Surface isocyanate (NCO), which often forms in the NO + CO reaction on supported catalysts, was found to be located on the supports and not on the metals [229]. However, such species were not found on Ir(211) [232] and Ir (111) [233] under UHV conditions. However, such species were not found on Ir(211) [232] and Ir (111) [233] under UHV conditions.…”