Gui Fubing, Huang Yong, Wu Menghan, Lu Xilai, Hu Yongming, Chen Wanping
Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China.
Research Institute of Wuhan University in Shenzhen, Shenzhen 518057, China.
Materials (Basel). 2022 Feb 12;15(4):1367. doi: 10.3390/ma15041367.
A high long-term stability is crucial for room-temperature gas-sensitive metal oxide semiconductors (MOSs) to find practical applications. A series of Pd-SnO mixtures with 2, 5, and 10 wt% Pd separately were prepared from SnO and Pd powders. Through pressing and sintering, Pd-SnO composite nanoceramics have been successfully prepared from the mixtures, which show responses of 50, 100, and 60 to 0.04% CO-20% O-N at room temperature for samples of 2, 5, and 10 wt% Pd, respectively. The room-temperature CO-sensing characteristics were degraded obviously after dozens of days' aging for all samples. For samples of 5 wt% Pd, the response to CO was decreased by a factor of 4 after 20 days of aging. Fortunately, some rather mild heat treatments will quite effectively reactivate those aged samples. Heat treatment at 150 °C for 15 min in air tripled the response to CO for a 20 days-aged sample of 5 wt% Pd. It is proposed that the deposition of impurity gases in air on Pd in Pd-SnO composite nanoceramics has resulted in the observed aging, while their desorption from Pd through mild heat treatments leads to the reactivation. More studies on aging and reactivation of room-temperature gas sensitive MOSs should be conducted to achieve high long-term stability for room-temperature MOS gas sensors.
对于室温气体敏感金属氧化物半导体（MOS）而言，要实现实际应用，高长期稳定性至关重要。分别由SnO和Pd粉末制备了一系列Pd含量分别为2 wt%、5 wt%和10 wt%的Pd-SnO混合物。通过压制和烧结，从这些混合物中成功制备出了Pd-SnO复合纳米陶瓷，对于2 wt%、5 wt%和10 wt% Pd的样品，其在室温下对0.04% CO-20% O-N的响应分别为50、100和60。所有样品经过数十天的老化后，室温CO传感特性明显下降。对于5 wt% Pd的样品，老化20天后对CO的响应降低了4倍。幸运的是，一些相当温和的热处理能非常有效地使那些老化样品重新激活。对于5 wt% Pd的20天老化样品，在空气中150 °C热处理15分钟后，对CO的响应增加了两倍。据推测，空气中杂质气体在Pd-SnO复合纳米陶瓷中的Pd上沉积导致了观察到的老化现象，而通过温和热处理使其从Pd上解吸则导致了重新激活。为了实现室温MOS气体传感器的高长期稳定性，应开展更多关于室温气体敏感MOS老化和重新激活的研究。
