Humidity-Sensing Properties of Ag super(0) Nanoparticles Supported on WO sub(3)-SiO sub(2) with Super Rapid Response and Excellent Stability

Ag super(0) nanoparticles supported on WO sub(3)/SiO sub(2) nanocomposites were synthesized in two steps by using a sequential combination of in situ and wet impregnation loading processes. Initially, WO sub(3) (5 wt.-%) was loaded onto SiO sub(2) by using an in situ process, followed by impregnation of the WO sub(3)/SiO sub(2) nanocomposite with AgNO sub(3) (1, 3 and 5 wt.-%). After calcination, the Ag super(0) nanoparticles were located inside the pore channels of the Ag-WO sub(3)/SiO sub(2) complex nanohybrid. The humidity-sensing results show that the material exhibits excellent sensitivity, rapid response/recovery, stability, durability, and a relatively low hysteresis towards relative humidity (RH) at room temperature. In particular, the material shows a 3-fold higher sensitivity compared with that of WO sub(3)/SiO sub(2) along with very rapid response times. The huge improvement in sensitivity may be credited to the chemical and electronic refinement actuated by the Ag nanoparticles inside the pore channels of the WO sub(3)/SiO sub(2). The findings reported in this study will be helpful for the development of complex mesoporous hybrid nanocomposites with improved RH-sensing performance. The rapid response (6 s) and recovery time (8 s) of an Ag-WO sub(3)/SiO sub(2) nanocomposite is described. The results show that the material exhibits excellent sensitivity, stability, durability, and relatively low hysteresis between 11 and 98% relative humidity (RH) at room temperature.