Ceria Maintains Smaller Metal Catalyst Particles by Strong Metal-Support Bonding

Abstract

The energies of silver (Ag) atoms in Ag nanoparticles supported on different cerium and magnesium oxide surfaces, determined from previous calorimetric measurements of metal adsorption energies, were analyzed with respect to particle size. Their stability was found to increase with particle size below 5000 atoms per particle. Silver nanoparticles of any given size below 1000 atoms had much higher stability (30 to 70 kilojoules per mole of silver atoms) on reduced CeO2(111) than on MgO(100). This effect is the result of the very large adhesion energy (approximately 2.3 joules per square meter) of Ag nanoparticles to reduced CeO2(111), which we found to be a result of strong bonding to both defects and CeO2(111) terraces, apparently localized by lattice strain. These results explain the unusual sinter resistance of late transition metal catalysts when supported on ceria.

Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against Escherichia coli

“…The concentration of Ag + eluted from Ag/CeO 2 nanorods was much less than that eluted from nanoparticles, indicating that Ag/CeO 2 nanorods largely reduced the speed of silver elution, while the concentration of Ag + eluted from nanocubes was found to be moderate. Recent determination of metal adsorption energies from calorimetric measurements found strong interaction and bonding between Ag and CeO 2 [33] Consequently, the origin of different concentrations of Ag + eluted from variously shaped CeO 2 with different exposed crystal facets might be associated with the bond stability offered by the strength of the chemical bonds between Ag and the underlying oxide surface. The strong chemical bonding of Ag to CeO 2 might lead to the lower concentration of Ag + elution.…”

Graphene-based transition metal oxide nanocomposites for the oxygen reduction reaction

“…Transition metal oxides have been intensively studied to be widely used in various fields. In addition to its well-known superiority, the other predominant characteristics of transition metal oxides for their groundbreaking application in the ORR should be highlighted: (1) abundant hydroxyl groups are inserted on the surfaces of transition metal oxides, which could be further functionalized by genetic materials (DNA and RNA) for biological catalysts; 11 (2) crystalline construction of transition metal oxides often have strong interactions, which could prevent the agglomeration of metal particles and maintain small metal particle sizes; 12,13 (3) they have considerably higher alkaline corrosion resistance in the electrochemical environment compared to noble metal and carbon-based materials due to the stabilization of the high oxidation state of transition metallic elements. In the past decade, due to excellent nanocomposite catalysts, novel advanced material-based transition metal oxides were created.…”

A copper-phyllosilicate core-sheath nanoreactor for carbon–oxygen hydrogenolysis reactions

“…Notably, the loss of active surface area by metal-particle growth is a major cause of deactivation for many supported catalysts. Strategies to mitigate particle growth comprise alloying with a higher-melting point metal 8 , tuning the properties of individual nanoparticles 9,10 and increasing the metal-support interaction energy by using specific oxides as carriers 11 . However, these approaches are not generally applicable because they restrict chemical composition and functionality.…”