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

Pristine Bi2WO6 nanosheets and hierarchical WO3-Bi2WO6 microflowers were prepared via a facile hydrothermal technique. WO3-Bi2WO6 microflowers were assembled with thin nanosheets, where WO3 nanoparticles were uniformly loaded. The H2S sensing properties of pristine Bi2WO6 nanosheets and hierarchical WO3-Bi2WO6 microflowers were systematically investigated at room temperature. 20 WO3-Bi2WO6 microflowers sensor displayed the best sensing property towards ppb-level H2S compared with all other samples. The enhancement was ascribed to the catalytic effect of WO3 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 WO3-Bi2WO6 microflowers sensor in detecting the volatiles of Pangasius was also studied in this work. Therefore, the hierarchical WO3-Bi2WO6 microflower is a promising ppb-level H2S sensing material for environment monitoring and fish freshness detection.