Enhanced opto-chemical sensing of phenolphthalein using thermally stable au-supported Titania-silica nanocomposites

Detecting acidic and basic species at a dynamic pH range with rapid response is crucial in the analytical field. Sol- gel-based thermally stable titania nanoparticles (TNPs), TNPs doped silica nanocomposite (TSNC), and Au- supported TSNC (ATS-NC) are synthesized for phenolphthalein sensing. ATS-NC possessed porous nano- structure, uniform particles distribution, and crystallite size of 4 nm, roughness of around 19 nm, and thickness similar to 76 nm. ATS-NC exhibited large surface area similar to 251 m(2)/g and a pore volume around 0.2 cm(3)/g. ATS-NC displayed a larger pKa (negative log of the acid dissociation constant) similar to 10.3 compared to TSNC (similar to 10) and TNPs (similar to 9.8) at 553 nm. The rapid response time of ATS-NC is observed around 0.3 s against pH 12 compared to 0.36 s (TSNC) and 0.39 s (TNPs). Experimental findings suggested that ATS-NC has potential for quick and efficient pH sensing in various applications such as environmental monitoring and food science.