In recent years, with people’s growing awareness of environmental protection, regulations on automobile emissions are becoming stricter all over the world. In this context, much research has been on catalysts for purifying motor vehicle emissions. Li Xingang, Professor of Tianjin University conducted a study on Perovskite-Type Lean-Burning Nitrogen Oxide Trap Catalyst. Through the research, he found that Perovskite Catalyst, Rare Earth Perovskite Catalyst in particular, has the potential to replace the traditional precious metal catalysts.

At present, LNT technology is widely applied to lean burners, with platinum-based Pt / BaO / Al2O3 being the catalyst under normal circumstances. However, Pt / BaO / Al2O3 catalyst shows some inadequacies: the precious metal Pt is expensive; it is easily sintered and lost at high temperatures that would result in serious inactivation of the catalyst.

Compared to Pt-based catalysts, Perovskite Catalyst represents advantages of low price, high catalytic activity, anti-sulfur performance and stability at high temperatures. Furthermore, its redox performance can be regulated by changing the composition of its A and B-site elements. Therefore, Perovskite Catalyst has been used in an attempt to replace the precious metal catalysts in the catalytic elimination of motor vehicle exhaust pollutants.

NO oxidation and storage mechanism of BaFeO3-x perovskite catalyst under lean burn conditions

As previous research shows the addition of Fe in Pt / BaO / Al2O3 catalyst improves the sulfur resistance and the renewable performance of the catalyst, Professor Li and his research team designed a BaFeO3-x nitrogen oxide trap catalyst with a Perovskite structure. It demonstrates through experiment that this kind of catalyst effectively depresses sulfuration and improves renewable performance.

NO oxidation, storage and catalytic elimination mechanism of La0.7Sr0.3CoO3 rare earth perovskite LNT catalyst.

Based on the experiments on a Ba-Based Perovskite LNT Catalyst, Professor Li attempted to dope the Pd element in the B-site of Rare Earth Perovskite. The results show that this catalyst has a NOx-eliminating performance comparable to that of the Pt-based catalyst, and exhibits a much higher sulfur resistance. Moreover, it is not easily deactivated and has high regeneration efficiency.