Catalytic deoxygenation during cellulose fast pyrolysis using acid–base bifunctional catalysis

Abstract

Catalytic fast pyrolysis of cellulose was performed in a micropyrolyzer coupled with online product analysis by GC-MS/FID/TCD. Acid, base, a physical mixture of acid/base, transitional metal compounds and acid–base bi-functional catalysts were evaluated based on their deoxygenation performance. The bifunctional catalyst was prepared by acid treatment of a natural mixed metal oxide, serpentine. Using the same number of acid/base sites, all of the catalytic materials were used in pyrolysis for the deoxygenation comparison. The results showed that the bifunctional catalyst achieved the best balance between deoxygenation and yield of vapor products. It appeared that during catalysis, the acidic sites primarily promoted dehydration while the basic sites mainly promoted fragmentation reactions. Compared to a physical mixture of acid and base material, the bifunctional catalyst appeared to promote deoxygenation reactions more effectively presumably due to the presence of adjacent acid and base sites.