Non-crystal-RuO x /crystalline-ZnO composites: controllable synthesis and high-performance toxic gas sensors

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 10; no. 28; pp. 15136 - 15145
• Main Authors: Luo, Na, Cai, Haijie, Li, Xiaojie, Guo, Mengmeng, Wang, Chen, Wang, Xiaohong, Hu, Pengfei, Cheng, Zhixuan, Xu, Jiaqiang
• Format: Journal Article
• Language: English
• Published: 19.07.2022
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D2TA02856E

The construction of sensitive and durable sensitizers facilitates the development of metal oxide semiconductor (MOS)-based sensors with excellent gas sensing performance. Here, amorphous ruthenium oxide (RuO x ) doped with lithium ions was successfully synthesized, and employed as a sensitizer to enhance the gas response of ZnO sensing materials. The gas sensing test results show that amorphous RuO x has better sensitization effects on ZnO than crystalline RuO 2 at an optimum working temperature of 210 °C, such as a higher response, lower working temperature, better selectivity and faster response/recovery speed. The response of the RuO x /ZnO-1 sensor remains almost unchanged over a period of 60 days, while the RuO x sensitizer loaded on ZnO retains an amorphous structure after 60 days of working. Ex situ XPS also demonstrates that amorphous RuO x does not crystallize into polycrystalline RuO 2 at 210 °C. The enhanced gas-sensing performance of the RuO x /ZnO-1 sensor can be attributed to the abundant active sites and better catalytic performance of amorphous RuO x , as well as enhanced electronic transmission between RuO x and ZnO. This is the first report showing that amorphous RuO x can work stably as a sensitizer at high temperature (210 °C), which facilitates the widespread use of amorphous metal catalysts in various fields.