Scandium and copper co-doping effect on stability and activity to the NO direct decomposition of Ba₃Y₄O₉

Direct decomposition of NO on Ba₃Y₄O₉ doped with Cu and Sc was studied and it was found that co-doping of Sc and Cu into Ba₃Y₄O₉ was effective for increasing both lattice stability and NO decomposition activity. In particular, Ba₃Y₃Sc_0.6Cu_0.4O₉ (10 % Cu and 15 % Sc doping) catalyst showed N₂ and O₂ yield of 90 % and 99 %, respectively, in NO decomposition reaction at 700 ℃. Comparing with the pristine and single-metal doped system, the optimized catalyst showed superior long-term stability and increased activity under O_2, and water vapor co-existence conditions because of the increased stability of crystal structure, improved lattice oxygen mobility and weakened oxygen adsorption on the surface. TPD and in-situ FT-IR results suggested that the co-doping effect was assigned to the easier removal of surface NO₂⁻ or NO₃⁻ species which blocks the active site to NO decomposition.