Investigation on deactivation of Cu-Cr catalyst for direct ethanol dehydrogenation to ethyl acetate, acetaldehyde, and hydrogen

Abstract

BackgroundThe utilization of bioethanol by converting it into additional high-value-added products including acetaldehyde, ethyl acetate, and hydrogen impresses as an appealing strategy at the present. The Cu-Cr catalysts improved product formation on ethanol dehydrogenation. This research was to assess the stability of the reaction and the deactivation of the catalyst over protracted ethanol dehydrogenation. MethodsThe deactivation behaviors of 50 Cu-Cr catalyst on ethanol dehydrogenation reaction was investigated. The co-precipitation technique was used to synthesize the Cu-Cr catalyst, which was then reduced by a mixture of H2/N2 prior to the stability test in the ethanol dehydrogenation reaction. The fresh, reduced, and/or spent catalysts after being used in ethanol dehydrogenation were characterized using XRD, SEM-EDX, HR-TEM, H2-TPR, NH3-TPD, XPS, TGA, and TPO. Significant findingThe proportion of CuCr2O4, Cu+, and Cu0 active sites on the catalyst sample influenced catalytic activity. Based on the results, the activity was related to the oxidation state of copper-chromium in the Cu-Cr catalyst. Fascinatingly, the results of the ethanol dehydrogenation showed that the catalyst deactivation was caused by the change in the copper-chromium oxidation state via the hydrogen self-reduction process and the soft coke formation on active sites after prolonged ethanol dehydrogenation resulting in a decrease in catalytic activity.