Tailoring of Surface Acidic Sites in Co–MoS<sub>2</sub> Catalysts for Hydrodeoxygenation Reaction
Yijin Zhang, Tangkang Liu, Qineng Xia, Hongyan Jia, Xinlin Hong, Guoliang Liu
Abstract
CoMo sulfides are typical catalysts for selective hydrodeoxygenation (HDO) of phenolics to aromatics which is important in bio-oil upgrading. However, it is still a challenge to promote the intrinsic activity of Co–MoS2 catalysts. Defect chemistry provides a good option to improve surface reactivity in catalysis. In this work, we report a facile H2O2 etching method to tailor the concentration of surface acidic sites. The molar ratio of H2O2/MoS2 can be altered to tune sulfur defects on the MoS2 surface for stabilizing Co species to form CoMoS active sites. The optimized Co–MoS2-2 catalyst, with the highest concentration of acidic sites, exhibits 3.4 times higher activity than the Co–MoS2-0 sample in the HDO of p-cresol to toluene. It is also found the HDO activity shows a linear relationship with the amount of surface acid (both Lewis and Brønsted acid) over the Co–MoS2-x catalysts. We believe that the understanding of the role of surface acidity would provide new opportunities for the rational design of efficient Co–MoS2 catalysts.