Room temperature WO3-Bi2WO6 sensors based on hierarchical microflowers for ppb-level H2S detection

Pristine Bi 2 WO 6 nanosheets and hierarchical WO 3 -Bi 2 WO 6 microflowers were prepared via a facile hydrothermal technique. WO 3 -Bi 2 WO 6 microflowers were assembled with thin nanosheets, where WO 3 nanoparticles were uniformly loaded. The H 2 S sensing properties of pristine Bi 2 WO 6 nanosheets and hierarchical WO 3 -Bi 2 WO 6 microflowers were systematically investigated at room temperature. 20 WO 3 -Bi 2 WO 6 microflowers sensor displayed the best sensing property towards ppb-level H 2 S compared with all other samples. The enhancement was ascribed to the catalytic effect of WO 3 nanoparticles and the modified microstructure with large specific surface areas. Moreover, the n–n heterojunction structures also increase the thickness of electron depletion layer and potential barrier height, which could efficiently improve the sensing properties. The practical application of 20 WO 3 -Bi 2 WO 6 microflowers sensor in detecting the volatiles of Pangasius was also studied in this work. Therefore, the hierarchical WO 3 -Bi 2 WO 6 microflower is a promising ppb-level H 2 S sensing material for environment monitoring and fish freshness detection.