Flame-annealed porous TiO2/CeO2 nanosheets for enhenced CO gas sensors

CO sensor is helpful to monitor the working state of combustion equipment, such as industrial boilers and engines, and to ensure the production process and human life safety. However, balancing fast response/recovery and high response value for metal oxide CO sensors remains a challenge. In this work, based on band gap engineering, porous TiO 2 /CeO 2 NSs with different TiO 2 coupling amounts were prepared by hydrothermal method combined with flame annealing. The heterojunction composed of TiO 2 and CeO 2 narrowed the energy band width of the composite system and made the electron transmission more efficient, which endowed TiO 2 /CeO 2 NSs with good gas sensing properties. The results indicated that the response value of TiO 2 /CeO 2 NSs is 9.78 time that of CeO 2 NSs. Its ultrafast response/recovery time (2 s/6 s), good CO selectivity and wide CO monitoring range (500 ppb-5000 ppm) are also impressive. The TiO 2 /CeO 2 NSs sensor has great potential for rapid CO monitoring.