Catalytic depolymerization of Kraft lignin towards liquid fuels over bifunctional molybdenum oxide based supported catalyst

Catalytic depolymerization of Kraft lignin towards valuable liquid fuels and monomeric phenols has been a significant and extremely attractive target, but it remains a great challenge. Herein, we report a catalytic system consisted of bifunctional molybdenum oxide based supported catalyst for catalytic lignin hydroconversion into alkylated benzenes and phenols. In the meantime, the achieved yield of liquid product was 95% and petroleum ether extracted product was 65% at 300celcius for 12 h over 20%MoOx/ZIF-8@ZIF-67 catalyst. The calorific value was increased from 25.66 MJ/ Kg to 34.31 MJ/Kg. The characterization studies show the incorporation of MoOx species leads to the synergy between redox sites and acid sites. The product analysis and catalytic studies demonstrate its synergism to promote catalytic cleavage of C-O linkages via the coupled hydrodeoxygenation and alkylation reaction. The reasonable catalytic mechanism and redox cycle route of catalyst indicate that the cooperative catalytic system paves the way for high-efficiency waste lignin utilization.

Automated summary

In this study, a catalytic system using bifunctional molybdenum oxide based supported catalyst was developed for the conversion of Kraft lignin into valuable compounds with high yield and improved calorific value. Characterization studies revealed the synergistic effect between redox sites and acid sites due to the incorporation of MoOx species. The results suggest that the catalytic system shows promising potential for high-efficiency utilization of waste lignin.