On the bifunctional nature of Cu/ZrO2 catalysts applied in the hydrogenation of ethyl acetate

5 years ago

On the bifunctional nature of Cu/ZrO2 catalysts applied in the hydrogenation of ethyl acetate

The catalytic hydrogenation of ethyl acetate to ethanol was studied at ambient pressure in the temperature range from 463K to 513K using Cu/ZrO2 catalysts obtained by co-precipitation as a function of the Cu loading. The hydrogenation was established as a reproducible probe reaction by determining optimal reaction parameters without deactivation or thermodynamic limitations. Power-law kinetics were determined yielding an apparent activation energy of 74kJmol⁻¹ and reaction orders of 0.1–0.3 for H2 and −0.4 to 0.1 for ethyl acetate in the temperature range from 473K to 503K. Metallic Cu was found to be essential for the hydrogenation, but the catalytic activity was not proportional to the Cu surface area derived from N2O decomposition and temperature-programmed H2 desorption experiments identifying Cu/ZrO2 as bifunctional catalyst. The acidic sites of the ZrO2 matrix were probed by temperature-programmed experiments with ethyl acetate and NH3. Cu⁰ is assumed to provide atomic hydrogen by dissociative adsorption and spillover, but the reaction rate is more affected by the tight contact between the embedded Cu nanoparticles and the X-ray amorphous ZrO2 matrix.

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DOI: S0021951717301756