Magnetically Recoverable Bifunctional Catalysts for the Conversion of Cellulose to 1,2-Propylene Glycol

The use of cellulose instead of oil to produce 1,2-propylene glycol (1,2-PG) is of great significance for building a sustainable world. Herein, we synthesize Fe3O4@SiO2/Ru-WOx core-shell magnetically recoverable catalysts containing both Lewis acid and metal active sites using well-shaped Fe3O4@SiO2 core-shell magnetic nanospheres as the substrate. We investigated the catalytic performances of the bimetallic catalysts with various metals as well as different metal contents and WOx loadings for the conversion of cellulose to 1,2-PG. The results showed that Fe3O4@SiO2/10%Ru-20%WOx was more favorable for 1,2-PG production, with a 1,2-PG selectivity of 32.4% and a cellulose conversion of 96.8%. Our characterization and activity tests suggested that WOx on the Fe3O4@SiO2 nanospheres produced abundant Lewis acid sites to effectively promote glucose isomerization to fructose before glucose undergoes the retro-aldol condensation reaction. Moreover, the Ru further hydrogenated the C-3 intermediate to 1,2-PG. It was notable that the catalyst can be separated through a simple magnetic separation after the end of the reaction, and it still maintained high catalytic activity after 5 uses.