Supported Ni-La-O_x for catalytic decomposition of N₂O I: Component optimization and synergy

A series of Ni-La-O_x complex oxides with Ni/La integer molar ratios from 1 to 10 supported on pretreated cordierite ceramics were prepared by an impregnation method and tested for direct catalytic decomposition of N ₂O. The Ni-La-O_x complex oxides showed considerable synergy in N₂O decomposition compared with pure nickel oxide, and the supported Ni-La-O_x complex oxides exhibited much better catalytic performance in reactions. The promotional effects of material structure and synergy of Ni- and La-based oxides on catalytic performance for N₂O decomposition were systematically studied through characterization by XRD, N₂-BET, H₂-TPR, N₂O-TPD and XPS. The results show that the NiO and LaNiO₃ are major active solid-phases for catalytic decomposition of N₂O; the synergetic action between NiO and LaNiO₃ promotes oxygen mobility and desorption, and stabilizes the active site of Ni^II. Furthermore, a new reaction mechanism for N ₂O decomposition over the supported Ni-La-O_x catalysts is proposed.