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-dope...