The effects of thermal ageing on automotive catalysts

Automotive catalysts continue to be the focus of many research collaborations as companies endeavour to ensure optimum performance whilst mitigating environmental damage.

Research on Lean NO_x Trap (LNT) catalysts has drawn significant interest over recent years as they overcome the challenge of NO_x reduction to N₂ in oxidising environments. Although this catalytic system efficiently reduces the amount of toxic gases released into the atmosphere, over time they can deteriorate, mainly due to the effects of high temperatures they are exposed to, and the build-up of additive materials.

In this study, we see scientists from the Ford Motor Company, the University of Belfast, and the University of Glasgow study a tri-metal (Pt-Pd-Rh) fully formulated Lean NO_x Trap catalyst to evaluate the effects of hydrothermal treatment on its performance and structural properties.

Using X-ray absorption fine structure spectroscopy (XAFS) at Diamond, along with spatially resolved capillary inlet mass spectrometers (Spaci-MS) techniques, they were able to determine structural changes in the catalyst and follow the variations in the metal particle sizes upon increasing thermal load. The results show that ceria and platinum were the most affected components of the catalyst.

The Spaci-MS study enabled them to measure the distribution of adsorbed species along the channels of the aged sample during reduction and determine the levels of NO_x present.

This study helps to provide a better understanding of the LNT catalyst’s performance and durability under prolonged hydrothermal conditions.

Read the paper to find out more.