Acidity-Tuned CeZr–Al–O Nanocatalysts for Efficient Xylose-to-Furfural Conversion under Microwave Irradiation

The development of environmentally benign and efficient catalytic systems is essential for advancing green and sustainable biomass conversion processes. In this study, we report a series of nanostructured ternary mixed oxides based on alumina modified with 10 and 30 wt % ceria–zirconia, synthesized via a sol–gel method, for the catalytic dehydration of xylose to furfural under microwave irradiation. The catalysts were characterized by N2 adsorption, XRD, UV–vis, and XPS techniques, revealing high surface areas, small crystallite sizes of Ce, Zr, and Al, and tunable acidity comprising the Lewis acid sites modulated by the Ce and Zr contents. The CeZr(30)–Al catalyst demonstrated a furfural yield of 65% at 170 °C in 40 min, markedly superior to that of pure Al2O3, CeO2, and ZrO2, highlighting the benefits of oxide synergy and microwave-assisted heating. This approach not only reduces reaction time and energy consumption but also avoids the use of corrosive mineral acids, aligning with key principles of green chemistry. These findings demonstrate the potential of CeZr–Al ternary oxides as efficient, sustainable catalysts for lignocellulosic biomass valorization into platform chemicals.