Directed hydrogenolysis of “cellulose-to-ethylene glycol” using a Ni–WOx based catalyst

Abstract

Biomass is an important renewable resource in nature, and cellulose is a crucial component within it. The chemically directed conversion of cellulose into ethylene glycol offers a green alternative to traditional petroleum-based production methods. In this study, a multifunctional Ni–WO_x/SAPO-11 catalyst was designed. By optimizing the processing parameters of catalysts and the reaction conditions of them, it was demonstrated that this catalyst could efficiently catalyze cellulose into alcohol products through a series of tandem reactions such as hydrolysis, retro-aldol condensation, and hydrogenation under relatively mild conditions. The yield of ethylene glycol climbed from 4% (at 180 °C) to 66.6% (at 240 °C) with the increase of reaction temperature. Characterization (XPS, TEM, TPD/TPR) revealed that a reduction temperature of 500 °C maximized Brønsted acidity and W⁵⁺/W⁶⁺ ratios, enhancing C–C cleavage efficiency. Further increases in the reduction temperature would weaken the Brønsted acid on the surface of SAPO-11, but its surface area would also increase (mainly in the form of mesopores). The uniformly dispersed elemental tungsten could form new acidic sites on the catalyst surface; in combination with active Ni⁰, this high-temperature reduced catalyst could achieve the direct hydrogenolysis of cellulose to produce ethylene glycol, benefiting the efficient utilization of lignocellulosic biomass in the future.