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

Abstract

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 300℃ 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.