Complex-surfactant-assisted hydrothermal synthesis of one-dimensional ZnO nanorods for high-performance ethanol gas sensor

Regular one-dimensional ZnO nanorods were synthesized by a complex-surfactant-assisted hydrothermal method for high-performance ethanol gas sensor using the mixture of sodium dodecyl sulfate (SDS) and polyethylene glycol 400 (PEG400) with a molar ratio of 1:1 as the complex surfactant. [Display omitted] •Regular one-dimensional (1D) ZnO nanorods (ZNRs) with large aspect ratio were synthesized by a complex-surfactant-assisted hydrothermal method using a mixture of sodium dodecyl sulfate (SDS) and polyethylene glycol 400 (PEG400) as the complex surfactant.•1D ZNRs with a single crystal hexagonal wurtzite structure were 120 − 180 nm in diameter and 2.4 − 4.5 μm in length.•The surfactants of both SDS and PEG400 played a significant role in the formation of 1D ZNRs, and a possible growth mechanism was proposed.•1D ZNRs showed high response, fast response/recovery time, good selectivity, and reversibility to ethanol gas.•The excellent ethanol sensing performance of 1D ZNRs is ascribed to the large length-to-diameter, the one-dimensional structure, and the numerous crystal defects of the oxygen vacancies existed in the surface region of 1D ZNRs. One-dimensional (1D) ZnO nanorods (ZNRs) were synthesized by a facile and effective hydrothermal method using the mixture of sodium dodecyl sulfate (SDS) and polyethylene glycol 400 (PEG400) with a molar ratio of 1:1 as the complex surfactant. The microstructure and morphology were characterized using of X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results demonstrated that the ZNRs are of a single crystal hexagonal wurtzite structure, having a larger length-to-diameter ratio with more regular surface morphology compared with the ZnO products obtained in the presence of only SDS or PEG400. A possible growth mechanism was proposed based the mediation reaction of the complex surfactant. Gas sensing measurements indicated that the ZNRs assisted by the complex surfactant demonstrated excellent ethanol sensing properties at an optimal operating temperature of 300 °C, which could be ascribed to their large length-to-diameter ratio, one-dimensional structure, and numerous surface defects of oxygen vacancies.