A periodic DFT study of glucose to fructose isomerization on tungstite (WO3·H2O): influence of group IV-VI dopants and cooperativity with hydroxyl groups

Periodic density functional theory (DFT) calculations were carried out to investigate the mechanism of glucose to fructose isomerization over tungstite (WO3∙H2O). The isomerization reaction is catalyzed by under-coordinated W6+ sites. The reaction mechanism proceeds through an H-shift from C2 to C1 and involves a cooperative action of Lewis acidic tungsten sites with neighboring proton donors, which form a hydrogen-bonding surface network. Dopants of group IV-VI transition metals stabilize the pre-activated complex, which is the deprotonated open form of glucose adsorbed to the surface. In particular, calculation reveal that doping the tungstite structure with Nb5+ and Ti4+ ions is effective in lowering the overall barrier for glucose isomerizatio