Pd-Supported ECNU-28 Zeolite Nanosheets for High-Efficiency Reductive Etherification of Furfural to Bio-Based Ethers

The transformation of biomass-derived furan-based platform compounds into etherification products over Pd-based catalysts is an effective pathway for the production of fuel additives. Specifically, furfuryl ethyl ether (FEE) can be synthesized through the reductive etherification of furfural (FAL). However, the utilization of Pd-based catalysts in the reductive etherification is limited by high Pd loadings. Herein, ECNU-28 nanosheet, derived from a zeolitic precursor with the layered structure analogous to SZR framework, was utilized as a support for Pd loading (low as 0.2 wt.%), producing a bifunctional catalyst Pd/ECNU-28 for the furfural reductive etherification reaction. The large external surface area (148 m² g⁻¹) of ECNU-28 facilitates the access of the reaction substrates to the acid sites. Meanwhile, the moderate acid site strength of ECNU-28 reduces the ring-opening side reaction of the etherification product, and its special inclined 8-ring restricts the reductive etherification reaction to occur on the surface. The Pd/ECNU-28 catalyst exhibited a superior etherification product yield, up to 83.1%. In addition, providing much higher FEE productivity per gram of Pd (6648 mmol_FEE g_Pd⁻¹ h⁻¹) than previously reported catalysts. Benefiting from the inherent hydrothermal stability of aluminosilicate, the Pd/ECNU-28 catalyst possesses good recyclability and can undergo regeneration treatment through simple calcination.