Significant Reduction of the Formation of N2O and NH3 on an Efficient Three-Way PtRh Catalyst Modified by LaFeCu Perovskite

This work designed a series of three-way catalysts (TWCs) with and without the modification by La0.67Fe0.83Cu0.17O3 (LaFeCu) perovskite to reduce the formation of N2O and NH3 emissions from natural gas vehicles (NGVs). The modified PtRh catalyst was found to have an efficient TWC performance and to reduce the formation of N2O and NH3 significantly. The X-ray diffraction and CO-Fourier transform infrared results demonstrated the formation of Rhx species, which would reduce the formation of NCO*, the main precursor of NH3. In situ diffuse reflectance infrared Fourier transform spectroscopy was used to confirm that no NCO* groups were found on the modified catalyst. The X-ray photoelectron spectroscopy results revealed the increase in the Pt2+ content on the modified catalyst, promoting the decomposition of N2O. Also note that the modified catalyst produced far fewer N2O than the catalyst without modification in the model reaction of CO + NO. Our work would provide a solution to develop an advanced TWC for NGVs.