Gas sensing properties of nano-ZnO prepared by arc plasma method

Nanometer ZnO, ZnO-Fe were prepared by H-2+Ar are plasma method. Compared with coarse-grained ZnO, nano-ZnO evidently possesses grain-size effect and the operating temperatures shift toward a lower temperature (200 degrees C-300 degrees C). The sensitivity of ZnO increases with decreasing grain size. Nano-ZnO exhibits higher sensitivities to LPG and C2H2 than to H2 and CO. Compared with nano-ZnO and ZnO-Ag, nano-ZnO-Fe-Ag exhibits excellent selectivity to H-2 with high sensitivity at < 200 degrees C and the response time is less than 15s. Thus, nano-ZnO-Fe-Ag holds promise as a low-power selective H-2 gas sensor. (C) 1998 Acta Metallurgica Inc.