Study on ZSM-5 catalytic pyrolysis mechanism of cellulose based on the Py-GC/MS and the density functional theory

Abstract

In this study, Py-GC/MS and density functional theory (DFT) were used to analyze products and reaction mechanisms of cellulose undergone non-catalytic and catalytic pyrolysis by ZSM-5. The results showed that the main products of non-catalytic pyrolysis are furans, furfurals, aldehydes, ketones, carboxylic acids, esters and carbohydrate. While, in catalytic pyrolysis, the furan content decreased noticeably, and a new class of components (aromatic hydrocarbons) appeared. DFT studies exhibited that a hydrogen proton at acid sites of the catalyst was directly involved in most of the pyrolysis reactions of cellulose. Catalytic pyrolysis reduces the activation energy of dehydration and de-carbonylation by 40–70 kcal/mol and 86.05 kcal/mol, respectively, compared with non-catalytic pyrolysis.