Nb-based solid acid catalysts for green biomass exploitation

摘要

Dispersed Nb2O5 phases in silica matrices were synthesized by different routes: co-precipitation and sol-gel to prepare mixed oxide samples, and wet-impregnation to prepare supported oxide samples. All the Nb2O5-containing catalysts were studied for their main surface and bulk properties and tested in the dehydration reaction of fructose (FRU) to 5-hydroxymethyl-2-furaldehyde (HMF) in water at 100°C. The typical water-tolerant acidity of Nb2O5 was maintained in all the samples. By dispersing different amounts of Nb2O5 into silica, the surface acidity of the samples was modified, in particular the surface acid strength. The Nb2O5-contained samples were active in the FRU dehydration reaction to HMF without the deactivation effects which are observed over bulk niobia catalysts.