Gas-phase hydrodeoxygenation of guaiacol over Ni-based HUSY zeolite catalysts under atmospheric H2 pressure

Abstract

Hydrodeoxygenation (HDO) is considered as one of the most promising routes to upgrade bio-oil for high value-added chemicals. In the study, the gas-phase HDO of guaiacol in atmosphere and 350 °C over Ni-based catalysts modified by Fe, Ga, Ce, La, or Sm on HUSY zeolite support was carried on. The effect of promotors, bimetallic/monometallic catalysts and Ni loading on HDO activity was investigated. The results showed that phenols and aromatic hydrocarbon were the main products and Ni was the main metal active site. Compared with monometallic metal catalysts, the promoters, such as Fe, Ga, Ce, La, and Sm, inhibited the aggregation of Ni, promoted Ni dispersion, and improved the HDO activity of guaiacol significantly. The highest conversion of 98.36% was performed over 10%Sm-20%Ni/HUSY, and the highest degree of hydrodeoxygenation (HDO%) of 7.7% was obtained over 10%La–20%Ni/HUSY catalysts. For Ce, Ga, and Fe modified catalysts, hydroquinone selectivity was higher than that over La and Sm modified catalysts. However, for La and Sm modified catalysts, phenols selectivity increased, and more aromatic hydrocarbon was formed. The HDO activity was improved via increasing Ni loading. Direct deoxygenation and hydrogenation were the more reasonable reaction pathways for gas phase guaiacol atmospheric HDO over Ni-based bimetallic HUSY catalysts.