Corn stover-derived biochar supporting dual functional catalyst for direct sorbitol production from cellulosic materials

Abstract

Sorbitol is one of the top twelve platform chemicals and is industrially produced via glucose hydrogenation reaction. Direct sorbitol production from cellulosic material using a low-cost catalyst is a current challenge. In this study, corn stover-derived biochar supporting dual functional catalyst (Ru/S-CCS) was prepared and extensively characterized. The Ru/S-CCS catalyst was used for direct sorbitol production from microcrystalline cellulose at various reaction temperatures (180–220 °C), times (3–18 h), H₂ pressures (1–5 MPa), and Ru contents (1–5 %). The maximum sorbitol yield (66.3 wt%) and selectivity (66.1 %) were achieved at 220 °C for 6 h under 5 MPa H₂ with 5 % Ru. Various catalyst characterization techniques revealed that the acidic characteristics and metal hydrogenation sites of the Ru/S-CCS played a vital role in direct sorbitol production from cellulose. The sorbitol yield and selectivity could be enhanced by the vigorous interactive effect of sulfonic groups and Ru metal sites. The recycling performance of the Ru/S-CCS catalyst was explored under the optimal reaction conditions. Moreover, sorbitol production from glucose, raw CS, and pretreated CS was further investigated. Overall, the results of this study show that the CS biochar used in Ru/S-CCS preparation can be a competitive material for the catalyst preparation in sorbitol production, which may subsequently be used for designing large-scale sugar alcohol production.