N-pentanol sensor based on ZnO nanorods functionalized with Au catalysts

Abstract

• Au-ZnO nanorods were prepared by one-step solvothermal method. • Au catalysts regulated the thickness of initial depletion layer of ZnO nanorods. • Au catalysts greatly increased the adsorbed oxygen species on the surface. • The response of 2% Au-ZnO is 71.8 to 4 ppm n-pentanol and the response time is 1 s. • 2% Au-ZnO showed excellent selectivity to n-pentanol in various saturated monohydric alcohols gases. As one of the most promising “next generation” alcohol fuels, n-pentanol brings convenience to our lives as well as challenges. Realizing real-time monitoring of n-pentanol is important to the health of workers in chemical plants. In this work, a series of Au nanoparticles functionalized ZnO nanorods were prepared by a facile one-step solvothermal method. The electronic sensitization and chemical sensitization of Au nanoparticles regulate the thickness of initial depletion layer of ZnO nanorods and increase the amount of adsorbed oxygen species on the surface. The gas-sensing results showed that 2 mol% Au nanoparticles functionalized ZnO nanorods exhibited the highest response of 71.8 to 4 ppm n-pentanol at 260 °C, and showed much higher response than other various saturated monohydric alcohols with different carbon chain lengths. Moreover, the sensor possessed ultra-fast response speed (1 s), excellent stability, and a certain ability of moisture resistance. The sensor was heated at 350 °C to promote the desorption of n-pentanol. The surface depletion layer model and energy band theory were used to explain the enhanced gas-sensing performance. This work provides a suitable candidate for real-time monitoring of n-pentanol in chemical plants.