Structure of Copper Oxide Species Supported on Monoclinic Zirconia

Abstract

The structure of copper oxide species in Cu/ZrO 2 catalysts with monoclinic zirconia as a support was studied. The catalysts with various copper loadings (3−40 wt % of Cu) prepared by impregnation technique were characterized using N 2 O titration, X-ray diffraction (XRD) analysis, radial distribution function (RDF) of electron density, and high-resolution transmission electron microscopy (HRTEM). It was established that the Cu/ZrO 2 catalysts contained highly dispersed CuO particles along with the large ones. Geometrical similarity between the CuO and ZrO 2 monoclinic structures favors stabilization of the highly dispersed CuO particles on the support with low specific surface area.

Peculiarities of Thermally Activated Migration of Subvalent Impurities in Cu-Doped Y-Stabilized ZrO2 Nanopowders Produced From Zr Oxychlorides

“…As previously reported (Samson et al, 2014;Pakharukova et al, 2015), CuO plays a significant role in the catalytic activity of Cu-doped oxides. In our case, according to the observed CuO content on the surface of the grains, we expect a higher catalytic activity for the Cu-1 samples.…”

“…Copper, located on the grains surface or in its near-surface region, was accepted to be responsible for catalytic activity of the composite (Sun and Sermon, 1994;Samson et al, 2014;Pakharukova et al, 2015), its fungicidal properties (Sherif and Hachtmann, 1980), tribological behavior (Ran et al, 2007), and also ability to compact the ceramic (Ran et al, 2007;Kong et al, 2014). In this case, the nature of surface Cu species, their surface concentration and surface area play an important role.…”

“…For instance, the mechanical alloying of YSZ and metallic Cu powders, similarly to SOFC anode preparation (Gross et al, 2007;Sun and Stimming, 2007;Restivo and Mello-Castanho, 2009), leads to the formation of metallic Cu in the YSZ pores (i.e., on the grain surface), which provides good electron conductivity. The impregnation of ZrO 2 or YSZ powders with copper nitrates, used generally for catalyst preparation (Samson et al, 2014;Pakharukova et al, 2015), results in Cu localization on the grain surface or in near-surface region as dispersed or crystalline CuO or as metallic Cu.…”

Influence of the Incorporation of Basic or Amphoteric Oxides on the Performance of Cu-Based Catalysts Supported on Sepiolite in Furfural Hydrogenation

“…The metallic surface area was determined according to the methodology proposed by Pakharukova et al, by using the following equation [50]:…”

Effect of sintering parameters using the central composite design method, electronic structure and physical properties of yttria-partially stabilized ZrO2 commercial ceramics

“…3a, some bonds between the O-Zr-O atoms were projected out of the unit cell. In these unit cells the zirconium (Zr) atoms are coordinated to seven oxygens forming a heptahedron-type polyhedron with the configuration of distorted deltahedral [ZrO 7 ] clusters and the prescence of 7 vertices (V), 9 faces (F) and 14 edges (E) composed of eight triangular faces and one square face [54][55][56]. These [ZrO 7 ] clusters form irregular polyhedra in the lattice, and for each ZrO 2 ceramics we have verified, at different temperatures and times, that the deltahedral [ZrO 7 ] clusters exhibit a particular characteristics related to the differences in the O-Zr-O bond angles [57,58].…”