Ceria-zirconia supported gold catalysts

Abstract

This paper presents the most important achievements and conclusions coming from the contributions concerning ceria-zirconia supported Au catalysts for low temperature water gas-shift reaction and low-temperature CO oxidation. The usefulness of CeO 2 -ZrO 2 mixed oxides as supports for Au nanoparticles has been reviewed, mainly from the point of view of their contribution to those reactions. A special attention was paid to the active sites of CO oxidation and WGS reaction over Au/ceria-zirconia systems. Some aspects of the reactions mechanisms are also discussed. Ceriazirconia supported gold catalysts appear to be very promising systems, which have a potential to create a new quality in the catalysis of WGS reaction. Ceria-zirconia mixed oxides also seem to be very promising supports for Au nanoparticles in CO oxidation. They could find a practical application in ambient conditions, especially in air purification systems and a breathing apparatus. It is possible that gold could be usefully incorporated into automobile catalysts, considering that the price of other noble metals is rising rapidly. Their use in this application will, however, require demonstration of adequate stability at operating temperatures.

Tiny Species with Big Impact: High Activity of Cu Single Atoms on CeO2–TiO2 Deciphered by Operando Spectroscopy

“…With an in-depth investigation of the heterogeneous catalytic oxidation of CO, , one can gain fundamental new insights into the performance of catalysts and even make progress on important technical applications such as preferential oxidation of CO (PROX), − air purification, exhaust-gas emission treatment, − proton-exchange membrane fuel cells, , CO sensors, and CO 2 lasers . Noble metals such as Pt, Rh, Pd, and Au, either nonsupported or supported on ceria, zirconia, titania, and alumina, are typical catalysts for this reaction. − CeO 2 is widely employed due to the highly active and reversible Ce 4+ /Ce 3+ redox shuttle and its unique ability to store and release oxygen. − Moreover, the high reducibility of CeO 2 and its tendency to form surface defects, in particular the O-vacancy defects, are known to stabilize highly dispersed metal species against sintering during reaction. − In CO oxidation, ceria is supposed to activate and supply oxygen from the lattice across the metal/ceria interface to react with CO adsorbed on the nearby metal species. ,, Besides, small CeO 2 particles alone can directly oxidize CO, although at higher temperatures, which may be another reason for the enhanced activity associated with ceria catalysts . The combination of noble metals, such as Pd and Pt with CeO 2 is desirable for several applications.…”

Effect of Preparation Methods on Al2O3 Supported CuO-CeO2-ZrO2 Catalysts for CO Oxidation

“…Thus, design and synthesis of more cost-effective and affordable noble metal-free catalysts are of particular interest [11]. Second type, gold catalysts are for room temperature oxidation of CO [12]. These catalysts have a potential to be practically applied in ambient conditions, especially in air purification systems and breathing apparatus.…”

Low temperature oxidation of CO using alkali- and alkaline-earth metal-modified ceria-supported metal catalysts: a review

“…There are variety of methods reported for emission control of CO, such as adsorption, absorption, thermal combustion, condensation, catalytic oxidation, etc. Among them, catalytic oxidation is the simple and affordable method for CO oxidation [4][5][6].…”