Fast responsive mesoporous silver supported silica nanocomposite for pH sensing

Silver (Ag) supported SiO2 nanocomposite is synthesized at low temperature (80 degrees C) by sol-gel method. The phenol red (PR) dye is encapsulated in Ag-supported SiO2 (PR/Ag-SiO2) nanocomposite for pH sensing at dynamic pH range 12. The PR/Ag-SiO2 nanocomposite possessed a crack-free porous nanostructure, crystallite size around 49 nm, large surface area (SBET) - 437 m(2)g(-1), and thermal stability at <= 400 degrees C. The PR/Ag-SiO2 exhibited pKa (negative log of the acid dissociation constant)10.9 at 558 nm, color response - 0.46 s in pH 12, repeatability without any leaching traces. Experimental findings suggest that PR/Ag-SiO2 has the potential for extreme aqueous media sensing for daily life applications.