One-step thermal compensation decomposition synthesis of ZnWO4/WO3 composite with synergy of multiple structural effects for efficient trace H2S detection

WO3-based composites containing ZnWO4/WO3 heterojunction were prepared by a one-step thermal compen-sation decomposition process. The thermal compensation agent plays an important role in improving thermal decomposition efficiency, particle size and particle dispersion regulation. This process is very simple to mass produce spherical WO3 nanoparticles with excellent short-range electron transport ability, while abandons the cumbersome synthesis of eye-catching fancy structures. Core-shell-shaped and mulberry-type configuration of nanoparticles are the mainstream morphology of this process. They are endowed with excellent gas sensitivity to H2S, accompanied with strong selectivity and cycle stability, especially the low detection limit as low as 0.0783 ppm. A convincing gas-sensing mechanism with synergy of multiple structural effects have been proposed, including the temperature dependence of vacancy oxygen restricting the optimal working temperature of gas sensors, spherical nanostructures providing short distance of electron migration, and heterojunctions promoting electron migration. ZnWO4/WO3-heterojunction-based nanostructures prepared in situ by thermal decomposi-tion will have broad prospects in the detection of trace H2S.

Automated summary

WO3-based composites containing ZnWO4/WO3 heterojunctions were synthesized through a one-step thermal compensation decomposition process. The thermal compensation agent played a crucial role in enhancing the thermal decomposition efficiency, particle size, and particle dispersion regulation. This process allowed for the mass production of spherical WO3 nanoparticles with remarkable short-range electron transport ability, without the need for complicated synthesis procedures. The core-shell-shaped and mulberry-type nanostructures were the predominant morphologies obtained. These nanostructures exhibited excellent gas sensitivity to H2S, along with high selectivity and cycle stability, particularly with a low detection limit as low as 0.0783 ppm. A gas-sensing mechanism involving the synergistic effects of multiple structural factors was proposed, including the temperature-dependent vacancy oxygen, spherical nanostructures facilitating short electron migration distances, and heterojunctions promoting electron migration. The in situ prepared ZnWO4/WO3-heterojunction-based nanostructures through thermal decomposition hold promise for the detection of trace H2S.