Ultrasensitive ppb-level trimethylamine gas sensor based on p–n heterojunction of Co <sub>3</sub> O <sub>4</sub> /WO <sub>3</sub>
Jiyang Zeng, Rong Qian, Bin Xiao, Baoye Zi, Xinya Kuang, Xiyu Deng, Yiwen Ma, Zhenlin Song, Genlin Zhang, Jin Zhang, Qingju Liu
Abstract
Abstract Trace poisonous and harmful gases in the air have been harming and affecting people’s health for a long time. At present, effective and accurate detection of ppb-level harmful gas is still a bottleneck to be overcome. Herein, we report a ppb-level triethylamine (TEA) gas sensor based on p–n heterojunction of Co 3 O 4 /WO 3 , which is prepared with ZIF-67 as the precursor and provides Co 3 O 4 deposited tungsten oxide flower-like structure. Due to the introduction of Co 3 O 4 and the 3D flower-like structure of WO 3 , the Co 3 O 4 /WO 3 -2 gas sensor shows excellent gas sensing performance (1101 for 10 ppm at 240 °C), superb selectivity, good long-term stability and linear response for TEA concentration. Moreover, the experimental results indicate that the Co 3 O 4 /WO 3 -2 gas sensor also possesses a good response to 50 ppb TEA, in fact, the theoretical limit of detection is 0.6 ppb. Co 3 O 4 not only improves the efficiency of electron separation/transport, but also accelerates the oxidation rate of TEA. This method of synthesizing p–n heterojunction with ZIF as the precursor provides a new idea and method for the preparation of low detection limit gas sensors.