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.