Direct decomposition of NO into N2 and O2 over Ba3Y3.4Sc0.6O9

Effects of dopant on direct decomposition of nitric oxide (NO) over Ba3Y4O9 were investigated and it was found that Sc is partially substituted Ba3Y3.4Sc0.6O9 catalyst shows a high NO decomposition activity (N-2 yield: 92%) at 1123K among the examined dopants. Sc is considered to contribute to the stabilization of the Ba3Y4O9 crystal phase and also form the intrinsic oxygen defects. This catalyst was active in NO decomposition in the presence of O-2 and maintained its high activity at high space velocity values. Fourier transform infrared spectroscopy (FT-IR) measurement suggests that initial adsorption state of NO is a bent-type NO-. Moreover, the rate-determining step for NO decomposition seems to be the coupling of the NO species adsorbed on the surface. Doping with Sc effectively weakened the adsorption of NO species, resulting in the increased reactivity. FT-IR and temporal analysis of products (TAP) measurements suggested that N2O may be an intermediate species in NO decomposition. (C) 2011 Elsevier B.V. All rights reserved.