Nano-scaled tungsten-trioxide（WO3） powder is synthesized by sol-gel process using tungsten powder as material.The effect of cerium oxide（CeO2） additive on the sensitivity of final devices is investigated

especially to volatile organic compounds（VOCs） and significant enhancement is achieved

the highest sensitivity is found to shift to low heating voltage.The analysis from field-emission SEM reveals that grain boundary is pinned due to adding CeO2

which results in decrease in the average grain size of Ce-doped WO3and increase in the surface area

compared with the undoped ones.Complex impedance spectroscopy analysis indicates that the Ce ions mainly exist in WO3 grain boundary

which results in increase in grain boundary resistance and decease in grain boundary capacitance.The gas-sensing property of WO3nanomaterials is improved.