UV-enhanced CO sensing using Ga_2O_3-based nanorod arrays at elevated temperature

摘要

Monitoring and control of the gaseous combustion process are critically important in advanced energy systems such as power plants, gas turbines, and automotive engines. However, very limited gas sensing solutions are available in the market for such applications due to the inherent high temperature of the combustion gaseous atmosphere. In this study, we fabricated and demonstrated high-performance metal oxide based nanorod array sensors assisted with ultra-violet (UV) illumination for in situ and real-time high-temperature gas detection. Without UV-illumination, it was found that surface decoration of either 5 nm LSFO or 1 nm Pt nanoparticles can enhance the sensitivity over CO at 500℃ by an order of magnitude. Under the 254 nm UV illumination, the CO gas-sensing performance of Ga_2O_3-based nanorod array sensors was further enhanced with the sensitivity boosted by 125% and the response time reduced by 30% for the La_(0.8)Sr_(0.2)FeO_3(LSFO)-decorated sample. The UV-enhanced detection of CO might be due to the increased population of photo-induced electron-hole pairs, whereas for LSFO-decorated nanorod array sensor under UV illumination, the enhancement is through a combination of the sensitizing effect and photocurrent effect.