The Catalytic Pyrolysis Mechanism of Cellulose On ZSM-5: Based On Py-GC/MS And Density Functional Theory

Cellulose is one of the main components of terrestrial biomass. In this study, a zeolite catalyst (ZSM-5) was used to catalyze the pyrolysis of cellulose. The components produced during pyrolysis were tested by Py-GC/MS, and the pyrolysis mechanism was analyzed by density functional theory (DFT). The results showed that furans and sugars were the primary pyrolysis products. After catalytic pyrolysis, the furfural content was significantly lower than that of non-catalytic pyrolysis. However, the yield of aromatic hydrocarbons increased significantly, especially benzene, which increased from almost zero to 13.04%. DFT further explored the specific reaction pathway of catalytic pyrolysis. It was found that under the catalysis of ZSM-5, the catalyst directly participated in most cellulose pyrolysis reactions. Also, the electrophilicity of acid sites in the reaction system played an important role. Therefore, the catalysis of the molecular sieve can significantly reduce the energy barrier of each path. In generating aromatic hydrocarbons, the decarbonylation reaction and dehydration reaction of furfural can be completely catalyzed, thereby increasing the reaction rate of generating aromatic hydrocarbons. Some deoxygenation steps occurred during the reaction, which made the catalytic pyrolysis reaction easier to develop, and improved the bio-oil quality.