4.8 Article

Promoting effect exerted by WOx on Pt/ZrO2 catalysts during NOx reduction using H2 in the excess of O2

Journal

JOURNAL OF CATALYSIS
Volume 423, Issue -, Pages 129-144

Publisher

ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcat.2023.04.018

Keywords

NOx reduction; H2 reductant; NH3 formation; Pt catalyst; ZrO2 support; WOx promoter

Ask authors/readers for more resources

This study investigates the reduction of NOx by H2 using Pt/W/ZrO2 catalysts below 200 degrees C under O2-rich conditions. The catalysts with different tungsten loadings were thoroughly characterized, and catalytic investigations showed that the sample with 5 wt% W had the highest efficiency. The W promoter promoted the structure of the ZrO2 surface, leading to a high number of active Pt sites. In addition, a side reaction involving NHx species formed at the interface of Pt and WOx/ZrO2 was observed.
This work addresses the reduction of NOx by H2 under O2-rich conditions below 200 degrees C using Pt/W/ZrO2 catalysts with tungsten loadings from 0 to 14 wt%. Samples were thoroughly characterized by N2 physisorption, temperature-programmed desorption of CO, X-ray diffraction, laser Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with CO as probe molecule. Catalytic investigations showed the highest efficiency for the sample with 5 wt% W providing NOx conversion of 94 % and N2O selectivity of 15 %. The effect of W promoter is mostly attributed to structural promotion by isolated WO6 entities stabilizing the ZrO2 surface and leading to a high number of active Pt sites. By contrast, negligible electronic interaction between the promoter and Pt sites appears. Moreover, DRIFTS studies suggest that, in addition to the predominate NOx reduction by H2 on Pt sites, a side reaction occurs including NHx species formed at the interface of Pt and WOx/ZrO2. (c) 2023 Elsevier Inc. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.8
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available