The catalytic reduction of NO by H_2 on Ru_(0001): Observation of NH_(ads) species

摘要

Adsorption of NO and the reaction between NO and H_2 were investigated on the Ru(0001) surface by X-ray photoelectron spectro-scopy (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 H_2 and NO (total pressure = 10~(-4) mbar). After steady-state NO reduction, molecularly adsorbed NO in both the linear on-top and threefold coordinations, NH_(ads) and N_(ads) species were identified by XPS. The coverage of the NH_(ads) and N_(ads) species was higher after the reaction at 390 K than the corresponding values at 320 K. Strong destabilisation of N_(ads) by O_(ads) was detected. A possible reaction mechanism is discussed.