Effect of Gallium Loading on Reducibility and Dispersion of Copper-Based Catalyst

Abstract:

The effect of gallium-promoted copper-based catalysts has been investigated in connection with the characteristic of the active copper phase. CuO-ZnO-Ga₂O₃ catalysts with different gallium loadings were prepared using oxalate co-precipitation method. The effects of gallium loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR). The dispersion and metal area of copper were also determined by dissociative nitrous (N₂O) adsorption technique conducted on a metal dispersion analyzer (BELCAT). The TPR profiles showed that the presence of two different reduction regions in the CuO-ZnO catalysts can be attributed to the reduction of highly dispersed copper oxide species (reduced at 246 °C) and bulk-like CuO (reduced at above 390 °C). By contrast, the only low-temperature reduction peak was presented in the TPR profiles after the Ga₂O₃ loading was higher than 4 wt%. With the same molar ratio (Cu/Zn = 2:1), the reducibility of CuO-ZnO-Ga₂O₃ was found to be more facile than CuO-ZnO due to the lower copper oxide crystallite sizes of gallium-promoted catalysts. Higher Ga₂O₃ loadings resulted in an increase in both copper dispersion and metal surface area of all the catalysts studied in good agreement with the reduction behaviors in the TPR profiles, although all the gallium-promoted catalysts were slightly different for the reducibility.

• Periodical: Key Engineering Materials (Volume 659)
• Pages: 211-215
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.659.211
• Online since: August 2015
• Authors: Parncheewa Udomsap*, Somsak Supasitmongkol
• Keywords: Copper Dispersion, Dissociative Nitrous (N₂O) Adsorption, Gallium Loading, TPR

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