Gold-Iron Oxide Catalyst for CO Oxidation: Effect of Support Structure

Abstract

Gold-iron oxide (Au/FeO x ) is one of the highly active catalysts for CO oxidation, and is also a typical system for the study of the chemistry of gold catalysis. In this work, two different types of iron oxide supports, i.e., hydroxylated (Fe_OH) and dehydrated iron oxide (Fe_O), have been used for the deposition of gold via a deposition-precipitation (DP) method. The structure of iron oxide has been tuned by either selecting precipitated pH of 6.7-11.2 for Fe_OH or changing calcination temperature of from 200 to 600˝C for Fe_O. Then, 1 wt. % Au catalysts on these iron oxide supports were measured for low-temperature CO oxidation reaction. Both fresh and used samples have been characterized by multiple techniques including transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and temperature-programmed reduction by hydrogen (H 2 -TPR). It has been demonstrated that the surface properties of the iron oxide support, as well as the metal-support interaction, plays crucial roles on the performance of Au/FeO x catalysts in CO oxidation.

A Review on Iron Oxide‐Based Nanoarchitectures for Biomedical, Energy Storage, and Environmental Applications

“…Previously, several factors have been reported to enhance the catalytic activity of supported Au NPs at room temperature. Cui et al reported that the pH value during synthesis and the calcination temperature of the iron oxide support material could strongly affect their catalytic performance (Figure b,c). The catalytic activity of FeO x /Au catalysts was observed to increase with increasing pH values from 6.7 to 11.2 and such increase was suggested to be the result of stronger interaction between Au and iron oxide support exhibited by the Au–OH–Fe or Au–Fe–O structure.…”

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

“…Even though these studies were not focused on catalysis, they proved the feasibility of imaging various Au-based alloys by FIM; alloys which are now used for catalysis applications: AuMo [228] for the reverse water-gas shift reaction [229,230] or as N2 dissociation catalyst for the HaberBosch process [231], Au-Pt [224] for CO oxidation [49,232] and selective toluene oxidation [52], AuFe [226] for CO oxidation [233] and N2 dissociation catalyst for the Haber-Bosch process [231], and Au-Cu [225,234] for the water gas-shift reaction [235,236] and CO oxidation [50].…”

Surface Chemistry and Catalysis

“…Cui H.-Z. et al [12] studied low-temperature CO oxidation over Au/FeO x catalysts, employing two different types of iron oxide supports, i.e., hydroxylated (Fe-OH) and dehydrated (Fe-O) iron oxides, and different preparation procedures (precipitation pH, calcination temperature). Surface characterization by a series of advanced characterization techniques, i.e., high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy, was carried out to explore the relationship between the nature of the oxide matrix and the catalytic activity.…”

“…It consists of 14 high-quality papers, involving: a comprehensive review article on the surface analysis techniques that can be employed to elucidate the phenomenon of electrochemical promotion in catalysis [3]; two theoretical studies (Density Functional Theory, DFT) on H 2 O dissociation and its implications in catalysis [4,5]; two mechanistic studies by means of temperature-programmed desorption/surface reaction (TPD/TPSR) and/or operando spectroscopy on N 2 O formation over NO x storage-reduction (NSR) catalysts [6] and on methanol reforming over cobalt catalysts [7]; two articles on H 2 production by the steam reforming of ethanol [8] or diesel [9] over transition metal-based catalysts; two articles on the production of commercial fuels by Fisher-Tropsch synthesis [10,11]; two articles on Au-catalyzed CO oxidation [12] and preferential CO oxidation [13]; and three experimental investigations regarding the structure-activity correlation of NO oxidation to NO 2 over Mn-Co binary oxides [14], cyclohexene oxidation on TiZrCo mixed oxides [15] and alkene epoxidation on silica nanoparticles [16].…”