# Structure Driven Tuning of the Catalytic Performance of PtCe-Modified Zeolite ZSM-5 in the CO Oxidation

## TL;DR

This paper explores how modifying zeolite ZSM-5 with platinum and cerium affects its ability to efficiently convert carbon monoxide at low temperatures.

## Contribution

The study demonstrates that the order of metal deposition and redox treatment significantly influences the catalytic performance of PtCe-modified ZSM-5.

## Key findings

- Cerium deposited after platinum (Ce/Pt/Z) achieves 100% CO conversion at 120 °C.
- Redox treatment lowers the CO oxidation temperature to 110 °C for Pt/Ce/Z.
- Low-loaded Pt (0.2 wt.%) catalysts show complete CO conversion at 95 °C.

## Abstract

The catalytic oxidation of CO is of great technological importance for the treatment of vehicle and industrial exhaust gases. PtCe-catalysts of low-temperature CO oxidation were prepared by the impregnation of ZSM-5 zeolite (Z) with aqueous solutions of H2PtCl6 and Ce(NO3)3, varying the order of metal deposition and thermal treatment conditions. The relationships between structure transformations and catalyst performance were established based on the SEM, TEM, EDX, DRIFT, and X-ray photoelectron spectroscopies data. For the Ce/Pt/Z sample, in which cerium was deposited after platinum, the 100% CO conversion temperature was only 120 °C. The inverse deposition sequence of metals (Pt/Ce/Z catalyst) resulted in CO oxidation at a higher temperature that can be decreased to 110 °C by redox treatment. The prepared catalysts were also active in the CO oxidation in excess hydrogen (PROX) but were not selective enough. However, the activity of PtCe-modified ZSM-5 enhanced greatly in the repeated cycles of CO oxidation (TOX) after testing in PROX. It is suggested that enhancing the interaction between Pt and Ce is a key factor in tuning the catalyst performance. The 0.2 wt.% Pt catalysts showed the best performance and provided complete CO conversion at 95 °C, which is a pronounced result for low-loaded Pt catalysts.