Infrared (IR) chemiluminescence studies of CO2 formed during steady-state CO + NO reaction over Pd(1 10) and Pd(1 11) surfaces were carried out. Kinetics of the CO + NO reaction were studied over Pd(1 10) using a molecular-beam reaction system in the pressure range of 10(-2)- 10(-1) Torr. The activity of the CO + NO reaction on Pd(1 10) was much higher than that of Pd(1 11), which was quite different from the result of other experiments under a higher pressure range. On the basis of the experimental data on the dependence of the reaction rate on CO and NO pressures and the reaction rate constants obtained by using a reaction model, the coverage of NO, CO, N, and O was calculated under various flux conditions. From the analysis of IR emission spectra in the CO + O-2 reaction on Pd(1 10) and Pd(1 11), the antisymmetric vibrational temperature (Tv(AS)) was seen to be higher than the bending vibrational temperature (T-V(B)) on Pd(1 10). In contrast, Tv(B) was higher than T-V(AS) on Pd(1 11). These behaviors suggest that the activated complex for CO2 formation is more bent on Pd(1 10) than that on Pd(1 10), which is reflected by the surface structure. Both T-v(B) and T-v(AS) for the CO + O-2 reaction on Pd(1 10) and Pd(1 11) increased gradually with increasing surface temperature (Ts). On the other hand, in the case of the CO + NO reaction on Pd(1 10) and Pd(1 11), T VAS decreased and T-V(B) increased significantly with increasing T-S. T-V(B) was lower than T-V(AS) at lower T-S, while T-V(B) was higher than T-V(AS) at higher T-S. Comparison of the data obtained for the two reactions indicates that T-V(B) in the CO + NO reaction on Pd(110) at T-S = 800 and 850 K is much higher than that in the CO + O-2 reaction on Pd(1 10).