Work

Novel and active Bi2Zr1.9M0.1O7 (M = Mn, Fe, Co, Ni) catalysts for soot particle removal: Engineering surface with rich oxygen defects via partial substitution of Zr‐site

Year: 2024

Type: article

Abstract: To obtain more cost‐effective, non‐noble catalysts for soot particle combustion of diesel engine cars, Bi2Zr1.9M0.1O7 (M = Mn, Fe, Co, Ni) compounds with partial lattice substitution have been designed and synthesized. All the substituted catalysts show significantly promoted activity, in the order of Bi2Zr2O7 < Bi2Zr1.9Ni0.1O7 < Bi2Zr1.9Co0.1O7 < Bi2Zr1.9Fe0.1O7 < Bi2Zr1.9Mn0.1O7. The presence of NO improves the activity of all the samples due to the generation of active surface nitrates/nitrites. It has been proven that all the modified catalysts possess weaker Zr–O bonds, which facilitates the generation of more surface defects. Density functional theory calculations have confirmed that a more defective catalyst has a lower vacancy formation energy and O2 adsorption energy. Isotopic 18O2 labeling has also substantiated that a more defective catalyst has a faster gaseous O2 exchange rate, thus improving the generation of more abundant soot reactive oxygen sites. The weakening of Zr‐O bonds is the inherent factor to improve the catalytic activity. Mn‐substitution can lead to the weakest Zr‐O bonds in Bi2Zr1.9Mn0.1O7, which thus shows the optimal catalytic activity. Notably, the complete soot combustion can be achieved even at 360°C on this catalyst.

Source: EcoEnergy

DOI: 10.1002/ece2.64