Effect of the surface acid sites of tungsten trioxide for highly selective hydrogenation of cellulose to ethylene glycol

This work studied a facile and template-free hydrothermal route for controlled synthesis of tungsten trioxide in the form of hexagonal nanorod (h-WO 3 ) and monoclinic nanosheet (m-WO 3 ). The surface morphology, crystal plane, surface bound water, and surface acid sites of the two kinds of WO 3 nanocrystals were investigated systematically. They were further evaluated as catalysts for selective cellulose hydrolysis. While both of them exhibited good catalytic performance, h-WO 3 was found to be more preferential for ethylene glycol (EG) generation. This catalytic performance relied on both the unique active crystal surface (1 0 0) and surface binding water (WO 3 -H 2 O) formed by h-WO 3 crystals, which provided more Lewis acid sites for degrading cellulose into EG . Results showed that the highest EG yield reaches 77.5% by a combination of loading 1 wt% Ru on the h-WO 3 catalyst.