Deactivation mechanistic studies of copper chromite catalyst for selective hydrogenation of 2-furfuraldehyde

Deactivation mechanisms of copper chromite (CuCr2O4⋅CuO) catalyst for vapor-phase selective hydrogenation for furfuryl alcohol have been investigated using ex situ and in situ X-ray absorption fine structure (XAFS), X-ray photon spectroscopy (XPS), and Auger Electron Spectroscopy (AES). At 200 °C, the catalyst steadily deactivated. One of the dominant origins of catalyst deactivation is poisoning due to strong adsorption of polymeric species formed from the reactant and/or products. Metallic Cu is identified as the active site, while loss of active Cu(I) sites due to hydrogenation is not a deactivation cause, as opposed to previous literature reported. The copper chromite catalyst showed low activity at 300 °C process temperature. Under this condition, the Cu particle size does not change, but Cr/Cu ratio increases by 50%, suggesting that Cr coverage of Cu sites becomes an additional cause of catalyst deactivation at this temperature, along with the poisoning deactivation mechanism at 200 °C.

During the hydrogenation of furfural, metallic Cu (not Cu(I) as stated in the literature) is identified as the active site. In situ spectroscopies show that catalyst deactivation is due to adsorption of both polymeric carbon species and Cr onto the Cu particle.Figure optionsDownload high-quality image (32 K)Download as PowerPoint slideHighlights
► Work on the deactivation of copper chromite biomass hydrogenation catalyst.
► Metallic Cu (not Cu(I)) is identified as the active site for furfural hydrogenation.
► In situ spectroscopies show deactivation is due to adsorption of polymeric species.
► During furfural hydrogenation, the Cu particle becomes covered with Cr.
► The coverage of Cu sites by Cr is an additional cause of catalyst deactivation.