Highly sensitive and selective ethanol sensor based on Sm2O3-loaded flower-like ZnO nanostructure

Abstract

In this investigation, the influence of Sm2O3 on the sensitivity and selectivity of ZnO flower-like sensors for selective detection of C2H5OH in the presence of CH4, CO and toluene is studied. Samples of ZnO loaded with 2, 5 and 10wt% Sm2O3 were prepared by employing a microwave assisted method using aqueous solutions of zinc acetate, samarium nitrate, and guanidinium carbonate as a structure directing agent. The samples were characterized by SEM, EDX, XRD, DRS UV–vis, and BET surface area techniques. Hexagonal wurtzite structure of ZnO is formed for all the samples calcined at 600°C. The sensors’ responses were measured in presence of 500ppm of CO, toluene, ethanol and 1.0vol% of methane in air at 200–400°C. As 5wt% Sm2O3 is added to ZnO, significant enhancements in the response to ethanol at various temperatures are observed, while it shows negligible responses to CO, toluene and methane. At 300°C, the response of 5wt% Sm2O3–ZnO sensor to ethanol is 60 times larger than that of pure ZnO. The Sm2O3–ZnO sensors show no or little response to methane, toluene and CO.