三种纳米结构三氧化钨的气敏性研究

摘要

Utilizing ammonium metatungstate [(NH4)6W12O40] as raw material, we produced three kinds of nanostructured WO3 under the same reaction conditions by controlling the concentration of citric acid (C 6H8O7). The nanostructured WO3 was characterized by XRD, SEM and TEM. Then, three kinds of gas sensors including WO 3 nanorod gas sensors, WO3 nanoplate gas sensors and WO3 nanoplateanorods mixing gas sensors were further manufactured. The sensitivity was measured for three kinds of nanostructured WO 3 gas sensors under the condition of acetone, ammonia and formaldehyde gas respectively. Experimental results show that the sensitivities of the three kinds of nanostructured WO3 firstly increase and then decrease with the increase of temperature at gas concentration of 1 000 ×10-6. In contrast, the sensitivity of WO3 nanoplate gas sensors is the highest among the three kinds of nanostructured WO3 for the three kinds of gases in the range of measuring temperature. The optimum operating temperature of WO3 nanoplate gas sensor is 350 ℃, 300 ℃, 325 ℃, 250 ℃ and its maximum sensitivity is 25.4, 18.52, 30.29, 18.31 in acetone, ammonia and formaldehyde gas, respectively. The sensitivity of the three kinds of nanostructured WO3 firstly increases and then decreases with the increase of temperature in the acetone gas of 50 × 10-6 and the formaldehyde gas of 100×10-6, respectively. The sensitivity of WO3 nanoplate is obviously higher than that of other two nanostructured WO3. At the optimum operating temperature, the acetone and formaldehyde gas with lower concentration can be detected by using nanoplate WO 3 gas sensor.%试验以偏钨酸铵为钨源，采用水热法在相同的反应条件下，通过控制柠檬酸的加入量，合成了三种纳米结构的三氧化钨，并采用XRD、SEM和TEM对合成的WO3粉末进行分析。纳米棒、纳米板、纳米板棒状混合结构的WO3被制备成气敏元件，在丙酮、氨气和甲醛气体下分别对三种气敏元件进行了气敏性测试。试验结果表明：在三种气体浓度都为1000×10-6的条件下，三种纳米结构的三氧化钨的气体灵敏度都随温度的升高先增大后减小，在整个测试温度范围内，纳米板状三氧化钨气敏元件与其他两种气敏元件相比灵敏度最高，纳米板状三氧化钨气敏元件测试丙酮、氨气、甲醛气体的最佳工作温度分别为300℃、325℃和250℃，灵敏度的最大值分别为18.52、30.29和18.31；在丙酮气体浓度为50×10-6和甲醛气体浓度为100×10-6的条件下，三个气敏元件的灵敏度同样随着测试温度的升高呈现出先增大后减小的变化趋势，纳米板状三氧化钨的气体灵敏度明显高于其他两种纳米结构的三氧化钨的灵敏度。在最佳工作温度下，用纳米板状结构的WO3可以检测出低浓度的丙酮气体与甲醛气体。