Metal nanoparticles supported on WO3 nanosheets for highly selective hydrogenolysis of cellulose to ethylene glycol

Abstract

Although the conversion of cellulose to polyols is currently well-developed, the production of the considerably valuable ethylene glycol (EG) is still challenging. Reactions have long relied on the design of suitable catalysts to obtain a high selectivity and yield of EG. Herein, using well-shaped rectangular tungsten trioxide nanosheets as the substrate, we investigated the catalytic performances of various metal supported catalysts for the convertion of cellulose to EG. Results show that Ru/WO₃ is more favorable for EG production, with the highest EG yield of 76.3% over the 1% Ru/WO₃ nanosheet catalyst. Our characterizations and activity tests suggest that the embedding of Ru nanoparticles onto the WO₃ nanosheets produces more W⁵⁺ active sites under the same reduction conditions (NaBH₄ or H₂), which act as Lewis base sites to promote the glucose retro-aldol condensation reaction. Moreover, the Ru/WO₃ catalyst holds a portion of Ru in the form of amorphous RuO_x^δ+ phases, which could further increase the H⁺ released into an aqueous solution for cellulose hydrogenolysis. A possible catalytic mechanism for this hydrogenolysis process is accordingly proposed.