Tungsten oxide decorated silica-supported iridium catalysts combined with HZSM-5 toward the selective conversion of cellulose to C6 alkanes

Abstract

Herein, WOx–decorated Ir/SiO2 (W/Ir = 0.06) and HZSM-5 were coupled to selectively convert microcrystalline cellulose (MCC) into C6 alkanes. A 92.8% yield of liquid alkanes including an 85.3% yield of C6 alkanes was produced at 210 °C. Cellulose hydrolysis, glucose hydrogenation and sorbitol hydrodeoxygenation were integrated to produce alkanes via a sorbitol route. Ir-WOx/SiO2 showed high performance for hydrogenation and hydrodeoxygenation reactions after hydrolysis catalyzed by HZSM-5. The intimate contact between WOx and Ir enhanced the synergistic interaction through the electron transfer from Ir to WOx. The interaction strengthened the reduction capability of Ir for hydrogenations, as well as improved the adsorption and activation of C-O bonds on reduced WOx for deoxygenations. The monotungstate WOx species provided moderate Lewis acids to cooperate with Ir to accelerate hydrodeoxygenations with alleviated retro-aldol condensation to yield more C6 alkanes.