Designed synthesized step-scheme heterojunction of Bi2WO6 nanosheet supported on CuBi2O4 nanorod with remarkable photo-assisted gas sensing for N-butyl alcohol

Photo-assisted gas sensors for n-butyl alcohol detection have attracted considerable attention due to their great potential in safety production and human health. However, the sensitivity, selectivity and stability should be further improved for practical application. Herein, Bi2WO6 nanosheet supported on CuBi2O4 nanorod sensor was realized by the two-step hydrothermal method, and it exhibited excellent sensitivity and stability for n-butyl alcohol detection under blue LED light illumination at the operating work temperature of 110 °C with gas concentration from 0.5 to 800 ppm. Meanwhile, the gas concentration of n-butyl alcohol obtained from the sensor was comparable to that of GC analysis. Furthermore, the sensor showed lower responses to other 25 kinds of common organic gases including alcohols, aldehydes, benzenes and ketones compared with that of n-butyl alcohol. More attractively, the Bi2WO6/CuBi2O4 sensor maintained its stable photo-assisted sensing activity over 3 months. The excellent gas-sensing property was caused by light illumination and formation of Bi2WO6/CuBi2O4 heterojunction, leading to abundant active electrons and superoxide radicals. The S-scheme mode of charge transfer at the Bi2WO6/CuBi2O4 heterojunction was revealed by the in-situ XPS and in-situ ESR analyses. The results gained herein may be useful for rational design of S-scheme heterojunction in photo-assisted gas sensor for n-butyl alcohol analysis.