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.