PREPARATION, STRUCTURE AND GAS-SENSING PROPERTIES OF ULTRAMICRO ZNSNO3 POWDER

In this paper, the authors have developed a method of preparing coprecipitated powder precursors of ZnO-SnO2 complex oxide by using oxalic acid and ammonia as precipitants. The phase constituents, structure and average grain sizes of powder precursors calcined at 500-1000-degrees-C have been studied by means of XRD and TEM, which have an obvious influence on the conductance-temperature (sigma-T) characteristics and gas-sensing properties. It is advantageous for the powder calcined at lower temperatures (500, 600 and 700-degrees-C) to detect combustible gases. The perovskite type of ZnSnO3 is the dominant phase in the powder calcined at 600-degrees-C; it has a much better sensitivity and selectivity to C2H5OH gas than anti-spinel type Zn2SnO4, ZnO and SnO2. Therefore, it is reasonable to expect the appearance of a good alcohol sensor by using a ZnSnO3-based material with suitable additives.