LAUSR

A facile, rapid and environmental-friendly method was developed to prepare ZnO with different morphologies and superficial structures just using Zn(NO3)2 and hexamethylenetetramine (HMTA) as precursors by tuning nucleation rate. Rod-like ZnO-1 and ZnO-5, and irregular ZnO-10 and ZnO-20 were obtained as the amounts of the used reagents are 1, 5, 10 and 20 mmol, respectively. Compared to ZnO-1, the responses of ZnO-5, ZnO-10 and ZnO-20 toward ethanol were improved greatly, which could be attributed to their alternative active adsorbed oxygen species (O2−/O− for ZnO-5, ZnO-10 and ZnO-20, O2− for ZnO-1). It was proposed that the different active adsorbed oxygen species might result from the different activation of ethanol with the aid of ZnO. The response of ZnO-10 toward 50 ppm ethanol is 115, about five times higher than that of ZnO-1, and the best gas-sensing performance of ZnO-10 was deemed to result from its largest specific surface area and highest percentage of adsorbed oxygen.