Highly selective etherification of fructose and 5-hydroxymethylfurfural over a novel Pd-Ru/MXene catalyst for sustainable liquid fuel production

Abstract

Sustainable liquid fuel production from bio-oil compounds has attracted considerable attention in recent years. The catalytic etherification of 5-hydroxymethylfurfural (HMF) to ethoxymethylfurfural (EMF) is an effective approach for the production of liquid fuels. However, the development of high-performance and chemically stable catalysts has remained challenging. In this work, ultra-small Pd-Ru NPs were successfully immobilized on the surfaces of 2D MXene nanosheets (Pd-Ru/MXene) via fish sperm DNA-assisted microwave process. HR-TEM imaging results with SAED analysis showed that the hexagonal closed-pack (hcp) Pd-Ru NPs were grown on the surfaces of sheet-like MXene, thus enhancing the specific surface area of 117 m sup(2) g sup(-1) and providing a higher density of the acid-base sites. Furthermore, Pd-Ru/MXene was employed for the etherification of HMF into EMF. The results showed that the Pd-Ru/MXene catalyst exhibited 98 percent EMF yield and 100 percent HMF conversion with the prolonged usage of catalyst for five consecutive reuse cycles. Additionally, fructose was directly converted into EMF with a higher yield of 82 percent over the Pd-Ru/MXene catalyst at lower reaction conditions. The recyclability test of the used Pd-Ru/MXene catalyst demonstrated its chemical stability under prolonged usage for several hours and is therefore suitable for commercial renewable liquid fuel production.