The catalytic reduction of NO by H2 on Ru(0 0 0 1): Observation of NHads species

Adsorption of NO and the reaction between NO and H2 were investigated on the Ru(0 0 0 1) surface by X-ray photoelectron spectroscopy (XPS). Surface composition was measured after NO adsorption and after the selective catalytic reduction of nitric oxide with hydrogen in steady-state conditions at 320 K and 390 K in a 30:1 mixture of H2 and NO (total pressure = 10−4 mbar). After steady-state NO reduction, molecularly adsorbed NO in both the linear on-top and threefold coordinations, NHads and Nads species were identified by XPS. The coverage of the NHads and Nads species was higher after the reaction at 390 K than the corresponding values at 320 K. Strong destabilisation of Nads by Oads was detected. A possible reaction mechanism is discussed.