Trimethylamine gas sensor based on Cr 3+ doped ZnO nanorods/nanoparticles prepared via solvothermal method

Abstract

Cr 3+-doped ZnO nano-rods with different doping concentrations are prepared via solvothermal method. The doped ZnO nano-rods are characterized by X-ray diffraction and scan electron microscopy, respectively. It was found that no Cr 2O 3 peaks appeared in the XRD patterns of Cr 3+ doped ZnO when the mole ratio of Cr 3+/Zn 2+ was in the range of 1–10 mol%. The effect of Cr 3+ doping on the resistances of the Cr 3+-doped ZnO nano-rod sensors was investigated and the results revealed that all Cr 3+ did not enter the lattice of ZnO. The amount of Cr 3+ had a great influence on the response (Ra/Rg). The sensor based on 3 mol% Cr 3+ doped ZnO nano-rods (120 °C, 10 h) exhibited high response and good selectivity to trimethylamine, especially, the responses to 0.001 ppm and 0.01 ppm trimethylamine reached 1.2 and 6.8, respectively. The response time and the recovery time for 0.001 ppm trimethylamine were 120 s and 80 s, respectively.