Pd supported on alumina modified by phosphate: Highly phosphorus-resistant three-way catalyst for natural gas vehicles

Abstract Natural gas vehicles (NGVs) have less CO2 emission and have been attracting more attention. However, catalyst is needed to remove pollutants such as CO, NOx and unburned methane in NGVs’ exhausts. The development of catalysts with high resistance to chemical poisoning, especially to phosphorus poisoning induced by lubricating oil of NGVs’ engine, is a challenge. Herein, we developed a new strategy to improve the phosphorus resistance of model palladium catalyst using phosphate-modified alumina as support for NGVs. The catalysts were analyzed by N2-physisorption, X-ray fluorescence spectrum (XRF), X-ray diffraction (XRD), CO-chemisorption, in-situ DRIFTS and X-ray photoelectron spectrum (XPS). The results show that phosphate-alumina support helps the model catalyst maintain its textual properties, otherwise phosphorus species from lubricating oil would deposit on the surface of catalyst and block the catalytically active sites. Moreover, the relative content of active Pd0 on phosphate-modified alumina support will not decrease. Therefore, compared with conventional Pd catalyst on alumina, the model Pd catalyst on phosphate-modified alumina can show significantly enhanced phosphorus resistance under operating conditions for NGVs, and can nearly maintain its catalytic performance of removing pollutants upon phosphorus poisoning. Our work would provide a general method for development of catalyst with high performance for NGVs.