Effect of Neodymium on the Physico‐chemical Properties and N 2 O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Cu−Al and Co−Al (M/Al=0.8/0.2, molar ratio; M=Cu or Co) mixed metal oxides showed a moderate activity in N 2 O decomposition (deN 2 O) with full conversion at about 500–550 °C. Addition of Nd modified the physico‐chemical and catalytic properties of both Cu−Al and Co−Al materials, though an optimal Nd loading was required. The addition of Nd in Cu 0.8 Al 0.2 and Co 0.8 Al 0.2 with Nd/Co(Cu)/Al = 0.5/0.8/0.2 molar ratio, improved significantly their catalytic activity. In particular, the temperatures needed for full N 2 O conversion were 100 °C lower than those of the bare materials. Furthermore, the most active Nd 0.5 Co 0.8 Al 0.2 catalyst exhibited a stable 60 % N 2 O conversion at 450 °C for 50 h in presence of NO (200 ppm), O 2 (20,000 ppm) and H 2 O (2500 ppm). The enhancement in the activity of both Cu‐ and Co‐containing materials was related to the formation of CuNd 2 O 4 for Nd 0.5 Cu 0.8 Al 0.2 and NdCoO 3 for Nd 0.5 Co 0.8 Al 0.2 . The presence of CuNd 2 O 4 or NdCoO 3 accounted for changes in redox properties, e. g., easier reduction or faster release of oxygen, and in turn an increased catalyst activity in deN 2 O. The investigation of rare earth‐based catalysts for deN 2 O is limited in the scientific literature, while a comprehensive understanding of the involved active species may facilitate a knowledge‐based catalyst optimization.