High-efficient non-noble metal catalysts of 3D ordered macroporous perovskite-type La2NiB'O6 for soot combustion: Insight into the synergistic effect of binary Ni and B' sites

Double perovskite-type La2NiB'O-6 (B' = Mn, Fe, Co, Cu) catalysts with three-dimensional ordered macroporous (3DOM) structure were synthesized by colloidal crystal template method. 3DOM structure promotes the contact efficiency between soot and catalyst. The periodic arrangement of [NiO6] and [B'O-6] octahedrons in La2NiB'O-6 induces the formation of coordination unsaturated B-site ions. 3DOM La2NiB'O-6 catalysts exhibited super catalytic performance for soot combustion under the simulated exhaust, and their catalytic performances are dependent on the synergistic effect of binary Ni and B'-site ions. 3DOM La2NiCoO6 catalyst had the highest catalytic activity for soot combustion, i.e., its T-50, SCO2m, TONs and TOFOv values are 362 degrees C, 98.2 %, 7.80 and 0.151 h(-1), respectively. The mechanism was proposed that the synergistic effect of Ni and B' ions boosts the key step of NO oxidation to NO2. It is meaningful for the development of the non-precious metal catalysts during soot combustion.