Efficient lignin depolymerization with Ru- and W- modified bi-functional solid acid catalyst

Abstract

A novel Ru-modified composite catalyst, Ru-W/Sn-AlOx, was prepared, and the effects of the catalyst on lignin depolymerization were investigated in this study. The catalyst converted approximately 95% lignin into liquid product at 300 °C in 12 h and 2/3 of the liquid product could be soluble in petroleum ether. The petroleum ether (PE) soluble product was mainly composed of monomers, dimers and some trimmers. This indeed indicated that the catalyst could effectively depolymerize lignin into small-molecule products. 7.22% of monomers was obtained at 310 C for 12 h. Meanwhile, the catalyst effectively reduced the char formation to 2%. After the catalytic depolymerization, the higher heating value (HHV) of the liquid product increased from 25.7 to 32.4 MJ/kg. The product could be utilized as fuel additive or converted to biofuels. This catalysis system showed great potential in the conversion of lignin into biofuels.