Selective furfural hydrodeoxygenation over Cu-Fe catalysts with In-Situ Cu@Fe3O4 formation

Abstract

This study investigates Cu-Fe mixed oxide catalysts with varying Cu/Fe molar ratios (0.5 to 2) synthesized via a sol–gel method for vapor-phase FFR HDO. The catalysts were characterized using XRD, H2-TPR, NH3-TPD, N2 physisorption, FESEM and XPS to gain sights into their properties. The characterizations unveiled the critical role of Cu/Fe molar ratio in influencing the properties and performance of the catalysts in FFR HDO. Fe promoted the dispersion of CuO, especially at a Cu/Fe ratio of 1, revealing synergistic Cu-Fe interactions. Increasing Cu/Fe ratio enhanced the reducibility of Fe but diminished that of Cu. Extensive investigations were conducted to assess the impact of key parameters, including Cu/Fe ratio, temperature, contact time, reduction temperature and H2/FFR molar ratio. The Cu-Fe mixed oxide catalyst with Cu/Fe = 1 proved to the optimal catalyst, exhibiting > 99 % FFR conversion and 90 % 2-MeF selectivity at H2/FFR = 15, 230 °C, and 0.5 gFFR h−1 gcatalyst-1. The extended evaluation of catalytic activity demonstrated sustained high performance, with stable conversion and 2-MeF selectivity values of > 99 % and 90 % over a period of 12 h. Even after 24 h on stream, the conversion remained above 90 %. Subsequent regeneration study showed partial recovery of the activity, with the catalyst maintaining conversion and selectivity consistently at about 85 % and 86 %, respectively for 10 h. Catalyst deactivation was a result of the site and/or pore blockage caused by the adsorption of FFR and FAL as well as the formation of oligomeric compounds on the catalyst’s surface.