Gas sensitivity study of polypyrrole/WO_3 hybrid materials to H_2S

摘要

Polypyrrole (PPy) and WO_3 were prepared by chemical oxidation polymerization and emulsion method, respectively. PPy/WO_3 hybrid materials with different PPy mass percent were prepared by mechanical mixing. WO_3 and PPy/WO_3 hybrids were characterized by XRD, SEM and HRTEM, and the sensitivity studies of PPy,WO_3 and PPy/WO_3 to toxic gases NH_3, H_2S, NO_x were also carried out. It was found that the particle size of WO_3 was about 29 nm, and PPy/WO_3 was about 50–100 nm. Gas sensitivity tests showed that when operated at 90 ℃, PPy/WO_3 hybrids had better reversibility to H_2S than PPy higher sensitivity and selectivity to H_2S than WO_3. PPy/WO_3 materials had short response–recovery time to H_2S and their sensitivities had linear relationship with the concentration of H_2S. The sensitive mechanism of PPy/WO_3 materials to H_2S may be the co-effect of proton doping process and the n-type semiconductor’s effect.