α - Fe2O3 nanopowders were prepared from Fe( NO3)3 · 9H2O and NaCO3 by the precipitation method. The shape and size of α - Fe2O3 nanopowders were characterized by TG - DTA, XRD and TFM techniques. The results showed that the morphology of the α - Fe2O3 nanopowders is spherical grains with the size about 40 nm. Obtained gas - sensing experimental results indicated that the α - Fe2O3 nanopowders presented high sensitivity and good selectivity to H2S, and much higher response than the commercial ones. The sensing mechanism of α - Fe2O3 sensors to the reductive gases was also discussed.%以Fe(NO3)3·9H2O和Na2CO3为起始物,采用化学沉淀法制备了纳米级a-Fe2O3粉体材料.采用XRD、TG-DTA和TEM等技术对产物的晶型、晶粒大小及形貌进行了表征.结果表明,沉淀法所制备的α-Fe2O3粉体材料为分散均匀的球形颗粒,平均粒径大小约40 nm.气敏性能测试结果表明该材料具有可观的气敏性能,对H2S气体表现出较高的灵敏度及良好的选择性,且对乙醇气体的灵敏度明显高于市售样品.在对所制备的α-Fe2O3纳米材料的结构及气敏性能进行系统研究的基础上,初步讨论了其对还原性气体的敏感机理.
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