Hydrocarbon Distribution of Cellulose Hydrogenolysis over Ru–MoO_<i>x</i>/C Combined with HZSM-5

Abstract

In this paper, acidic HZSM-5 coupled with the hydrodeoxygenation catalyst Ru–MoOx/C was applied for cellulose conversion to chain-mediated small-molecule alkanes in a water-containing biphasic solvent. The physicochemical properties of the binary catalyst Ru–MoOx/C were studied by an array of characterization methods. Meanwhile, the factors (such as the HZSM-5/Ru/MoOx ratio, reaction temperature, H2 pressure, and volume ratio of the aqueous phase and organic phase) that influenced the yield of natural gas (CH4), liquefied petroleum gas (C2–C4 alkanes), and gasoline (C5–C6 alkanes) were thoroughly investigated, obtaining the highest CH4 yield of 56.1% and the highest C5–C6 alkane yield of 66.1% by adjusting the volume ratio of the aqueous phase and organic phase, respectively. Especially, a promising yield of C2–C4 alkanes (43.7%) was obtained via precisely tailoring C–C bond splitting. HZSM-5 in water was proved as the solid acid for hydrolyzing cellulose to glucose, followed by transferring to Ru–MoOx/C located at the water–oil interface for further hydrogenolysis to alkanes. The fact that small-molecule alkane distribution can be controlled by Lewis acid density over Ru–MoOx/C was clarified: the lower Lewis acid density proved C1–C4 alkane production, while a higher Lewis acid density favored C5–C6 alkane production.