Hydrothermal synthesis of Ag-doped WO3-based H2S room temperature sensors: Unprecedented high and fast response

Ag-doped WO 3 nanoflower gas sensor was prepared for H 2 S gas detection by a simple one-step hydrothermal method . The synthesis process does not require any surfactant or template agent, which is in line with the development concept of "green chemistry". The microstructure, gas-sensitive properties and sensing mechanism of the sample were analyzed. The results show: Ag@WO 3 is a self-assembled nanoflower-like structure, which provides channels for gas diffusion and transport. Additionally, the Ag@WO 3 sensor can detect a high response value of 10 ppm H 2 S (11420) at room temperature (R.T.), which is approximately 941 times that of WO 3 (Ra/Rg = 12.14，R.T.). Response time is only 7 s and detection limits are as low as 10 ppb. The proposed Ag@WO 3 sensor represents a significant advance in gas detection in terms of its performance and application feasibility. This significant improvement in performance is mainly attributed to the three-dimensional stratification structure, the electronic and chemical sensitization of Ag, and the sulfurization reaction of Ag with H 2 S. Based on experimental and theoretical analysis, the proposed Ag@WO 3 nanoflower material is expected to overcome the limitations of traditional WO 3 sensors, and provides a promising way for the application of Ag modified WO 3 -based H 2 S gas sensors. • Ag@WO 3 nanoflowers with multi-gas dispersion channels have been prepared firstly. • Ag doping makes WO 3 -based sensors show unprecedented high performance. • The response value of Ag@WO 3 to 10 ppm H 2 S at room temperature is 11,420. • The effect of O L and O V content on the dynamic response is explained in detail.