In situ FTIR studies of CO oxidation over Fe-free and Fe-promoted PtY catalysts: Effect of water vapor addition

Abstract

In the quest of better CO elimination catalysts, Fe oxide was employed to promote platinum supported on HY zeolite. Fe-free and Fe-promoted PtY catalysts were prepared by ion exchange method and calcined at 500 °C. The prepared samples were characterized using XRD, FTIR, TEM, CO adsorption and CO-TPD. The particles size calculated from XRD patterns and TEM images was ≈18–20 nm in PtY and ≈8–15 nm in PtFeY. The CO removal performance over the prepared solids has been investigated by means of in situ technique using FTIR spectroscopy. Platinum surface modified with Fe oxide has a pronounced catalytic activity towards the CO oxidation more than Fe-free Pt containing catalyst. Reduction of the prepared catalysts with H 2 gas prior to admission of gas mixtures increased the catalytic activity more than that of as prepared catalysts. A strong positive water-effect was established when a trace amount of water (more realistic conditions) was added to the gas mixture (CO + O 2) during the CO oxidation particularly over PtFeY. In presence of water, the amount of CO 2 adsorbed over PtFeY is ≈5 and ≈600 times more than that of water free reaction over PtFeY and PtY catalysts, respectively.