Au/CeO2 metallic monolith catalysts: influence of the metallic substrate

L M Martínez Tejada,O Sanz,J A Odriozola,M I Domínguez,M A Centeno

doi:10.1007/s13404-013-0102-0

Abstract

Ceria-based gold catalysts were successfully deposited on ferritic stainless steel (Fecralloy) and aluminium monoliths. The prepared monolithic and reference powder catalysts were characterized by means of S BET, X-ray diffraction, glow discharge optical emission spectroscopy and scanning electron microscopy–energy dispersive X-ray analysis techniques and tested in the CO oxidation reaction. Characterization results put in evidence the diffusion of cations from the catalytic layer on the surface of the monoliths to the metallic oxide scale and inversely, from the oxide scale to the catalysts, thus altering the catalytic formulation and affecting the CO oxidation properties of the catalytic device. The extension and nature of the modifications produced depend on the nature of the catalysts and the metallic substrate, as well as the reaction conditions applied. These facts must be considered when gold catalysts are supported on metallic-structured devices.

Highlights

Heat and mass transport properties are strongly enhanced by using structured catalysts and reactors that offer high precision in catalysis at all relevant scales of the catalytic processes
From the Scanning electron microscopy (SEM) analyses of the cross section (Fig. 1a), the thickness of the oxide layer is ≈3 μm, in good agreement with that estimated from glow discharge optical emission spectroscopy (GD-OES) measurements (3.8 μm) (Fig. 1b)
In the Fecralloy monoliths as well as in anodised aluminium ones, the successful deposition of the catalytic layer was confirmed by SEM-EDX, being the adherence excellent whatever the catalyst deposited (≈99 % of the coating is retained after ultrasonic test)

Summary

Introduction

Heat and mass transport properties are strongly enhanced by using structured catalysts and reactors that offer high precision in catalysis at all relevant scales of the catalytic processes. We have selected Au/CeO2 (0.1 and 1 wt.%) and CeO2 as catalysts to be deposited on monoliths prepared with two different metallic substrates, a ferritic (Fecralloy) stainless steel and anodised aluminium.

Objectives

Results

Conclusion