Cellulose is the most abundant biomass in nature, and its catalytic conversion to commodity chemical ethylene glycol represents an important advance towards sustainable chemistry. In previous work, we have shown that tungstic acid plays a key role in selective C-C cleavage to form glycolaldehyde and then ethylene glycol. To further enhance the efficiency of tungstic acid, a series of additives were investigated in this work. Among various acid additives, H2SO4 stands out as the most remarkable additive; ethylene glycol yield was enhanced from 32.6% to 52.6% at a H2SO4/H2WO4 molar ratio of 0.03 and a H2WO4/cellulose weight ratio of 0.05, that is, an extremely dilute acid concentration. Weakly acidic sulfates (e.g., CuSO4 and FeSO4) have also been demonstrated to be highly efficient additives to improve the catalytic efficiency of tungstic acid, through promoting the hydrolysis of cellulose. (C) 2015 Elsevier B.V. All rights reserved.