Characterization and Catalytic Functionalities of Copper Oxide Catalysts Supported on Zirconia

Abstract

A series of zirconia supported copper oxide catalysts with varying copper loadings (1.2-19.1 wt %) were prepared by impregnation method. The catalysts were characterized by X-ray diffraction, UV-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and temperature-programmed desorption of CO2. Copper dispersion and metal area were determined by N2O decomposition method. X-ray diffraction patterns indicate the presence of crystalline CuO phase beyond 2.7 wt % of Cu on zirconia. UV-visible diffuse reflectance spectra suggest the presence of two types of copper species on the ZrO2 support. XPS peaks intensity ratio of Cu 2p3/2 and Zr 3d5/2 was compared with Cu dispersion calculated from N2O decomposition. TPR patterns reveal the presence of highly dispersed copper oxide at lower temperatures and bulk CuO at higher temperatures. The basicity of the catalysts was found to increase with Cu loading, and the activity of the catalysts was also found to increase with the increase in Cu loading up to 2.7 wt % Cu loading. The catalytic properties were evaluated for the dehydrogenation of cyclohexanol to cyclohexanone and were related to surface properties of the copper species supported on zirconia.

Catalytic combustion of toluene over copper oxide deposited on two types of yttria-stabilized zirconia

“…3, whereas the calculated surface compositions are summarized in Table 2. The binding energy of the Cu 2p 3/2 peak at 934.1 eV and the characteristic shake-up peak at a binding energy of about 944 eV display the presence of Cu 2+ species [14]. A higher concentration of Cu is found on the surface of the sZrY support, which confirms the observations based on the N 2 adsorption isotherms.…”

Multicomponent Synthesis of 1,2,3‐Triazoles in Water Catalyzed by Copper Nanoparticles on Activated Carbon

“…All peaks corresponding to the Cu (2p 3/2 ) level appear at higher binding energy when compared with those obtained with unsupported copper nanoparticles, [20] with the peak at 945.7 eV being a satellite shakeup feature characteristic of Cu 2+ species. [21] The selected-area electron-diffraction pattern (SAED) of the copper nanoparticles is also in agreement with the presence of Cu 2 O and CuO. It is worthy of note that mixed Cu/Cu-oxide [15c] and, very recently, CuO nanostructures [22] have been found to catalyse the 1,3-dipolar cycloaddition of azides and terminal alkynes.…”

Direct transformation of ethanol to ethyl acetate on Cu/ZrO2 catalyst

“…Broad peaks at 2h = 30.5°pointing to an amorphous or semicrystalline nature of the zirconia in these samples [12]. The absence of crystalline CuO or Cu 2 O peaks cannot be ruled out as they might be less than 40 Å in size, which is beyond the detection capacity of the XRD technique [13]. peak at 300°C appears, which has been attributed to the reduction of crystalline CuO to metallic copper.…”