Stability-enhanced Cu-based catalysts via Al doping and Nb promotion for conversion of furfural to 2-methylfuran

A ternary Cu-Nb/Al-MCM-41 catalyst achieves 99.60 % 2-methylfuran selectivity at 160 °C under atmospheric H2. • Al incorporation enhances metal dispersion and generates balanced Brønsted-Lewis acidity for controlled C O hydrogenolysis. • Nb promotion enables efficient H2 activation and strengthens Cu-Nb interfacial electronic coupling. • The catalyst exhibits excellent long-term stability and can operate continuously in a fixed bed for 500 h. The selective hydrodeoxygenation (HDO) of furfural (FAL) into 2-methylfuran (2-MF) is a crucial transformation for upgrading lignocellulosic biomass into liquid fuels. Herein, a series of Cu-Nb catalysts supported on mesoporous MCM-41 were developed. Over the optimized Cu-Nb/Al-MCM-41 catalyst, FAL was completely converted and the selectivity of 2-MF was 99.60 % at only 160 °C under ambient hydrogen pressure. Structural analyses revealed that Al incorporation reinforced metal-support interactions, enhanced Cu dispersion, and producing moderate Brønsted-Lewis acid sites, which synergistically facilitated hydrogen transfer and selective C O bond cleavage. In situ DRIFTS and XPS measurements confirmed a tandem hydrogenation-dehydration pathway proceeding via furfuryl-alcohol (FOL) intermediates, where Nb promoted H 2 activation and Al-derived acid centers accelerated dehydration at interfacial Cu-Nb-Al sites. The catalyst maintained high activity and selectivity during 500 h time-on-stream in a fixed-bed reactor, although slight deactivation was observed after prolonged operation. These findings establish a clear structure-function correlation between electronic modulation and acid-metal synergy, offering a sustainable strategy for efficiently producing furan-based biofuels under mild conditions. Download: Download high-res image (291KB) Download: Download full-size image