Pt-Fe2O3复合纳米陶瓷的室温氢敏性能研究

以Fe2O3纳米粉与铂粉为原料,通过压片与烧结,制备出了Pt-Fe2O3复合纳米陶瓷。SEM等分析表明,该陶瓷中存在大量纳米尺寸的孔洞,其Fe2O3晶粒粒径仅为30nm。以该陶瓷材料制备的氢气传感器,在室温下对氢气具有显著的响应。对氮气中5%氢气,其电阻下降90余倍,响应时间和在空气中的恢复时间分别约为20s和30s。为了揭示其室温氢敏机理,将氮气中氢气的浓度由5%降低至0,发现该陶瓷的电阻不随氮气中氢气浓度的下降而发生变化。该结果表明,Pt-Fe2O3复合纳米陶瓷的室温氢敏现象是由于氢在Pt的催化作用下与吸附氧在室温下发生化学反应而引起的。与之前报道的TiO2基陶瓷材料的室温氢敏现象相比,Fe2O3基陶瓷材料的室温氢敏性能与机理均存在显著的差别,因此有必要对金属氧化物半导体基陶瓷材料的室温氢敏现象进行深入系统的研究。

Room-temperature hydrogen sensing capabilities of Pt-Fe2O3 composite nanoceramics

Pt-Fe2O3 composite nanoceramics were prepared from Pt and Fe2O3 nanoparticles through traditional pressing and sintering. SEM analyses showed that numerous nanosized pores were present in the ceramics and Fe2O3 grains were around 30nm in size. Sensors based-on the nonoceramics were found to show strong responses to hydrogen at room temperature. To 5% H2 in N2, the sensitivity was over 90, and the response and recovery times were 20s and 30s, respectively. To explore the room-temperature hydrogen sensing mechanism, hydrogen concentration in surrounding N2 was decreased from 5% to 0. The resistance of the sensors was found to show no response to the hydrogen concentration variation. It indicates that hydrogen-induced decrease in resistance of Fe2O3 results from the reaction between chemisorbed oxygen on Fe2O3 and hydrogen at room temperature with the catalytic effect of Pt. Fe2O3 based ceramics are quite different from TiO2based ceramics in room-temperature hydrogen sensing properties and mechanism, and systematic investigations should be conducted on room-temperature hydrogen sensing of various metal oxide semiconductor ceramics.