Figure 6 - uploaded by Chaowat Autthanit
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Source publication
Three AgLi/SiO2 catalysts containing different types of silica supports [small particle size (SPS), medium particle size (MPS), and large particle size (LPS)] were prepared by incipient wetness co-impregnation techniques and tested in oxidative dehydrogenation of ethanol into acetaldehyde. The catalysts were characterized and evaluated by various c...
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Context 1
... the carbon dioxide temperature-programmed desorption (CO2-TPD) was performed. As seen in Figure 6, it can be observed that the CO2-TPD profiles were presented at the temperature from ca. 50-300 °C. The CO2-TPD profiles occur at low desorption temperature between 50-150 °C, which is referred to CO2 with weakly OH-groups adsorbed on the catalyst surface [42]. ...
Citations
Thermal transformation of copper incorporated hydrotalcite-derived oxides is investigated in ethanol dehydrogenation. Among the copper supported catalyst c-10Cu/HT600 prepared by impregnation of thermally treated hydrotalcite at 600 oC with Cu(NO3)2 solution followed by a calcination provides a high catalytic activity, selectivity and stability. XRD, DR-UV, TGA, H2-TPR, CO2-TPD, TEM and XPS techniques reveal that the nature of the copper species depended on the thermal treatment process and support. Such treatment at high temperatures yields a homogeneous dispersion mixed metal oxide. After copper incorporation generated CuAl2O4 spinel structure linked to the copper oxide species can suppress copper agglomeration leading to the catalytic stability. Moreover, the c-10Cu/HT600 catalyst can provide a high activity and high selectivity to acetaldehyde even at low reaction temperatures (200 oC). However, the copper species may agglomerate to form relatively larger clusters upon increasing metal loading leading to the deactivation.
