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

• Published in: Materials research bulletin 2025-03, Vol.183, p.113195, Article 113195
• Main Authors: Islam, Shumaila, Alshoaibi, Adil, Alnaim, Nisrin
• Format: Article
• Language: English
• Subjects: Opto-chemical sensing; Phenolphthalein dye; Sol-gel method; Thermal properties; Titania-silica nanocomposite
• ISSN: 0025-5408
• DOI: 10.1016/j.materresbull.2024.113195

•Sol-gel based Au-supported titania doped silica nanocomposite (ATS-NC) revealed thermal stability at ≤ 450 °C.•ATS-NC showed a dense porous morphology with a relatively high RMS of around 19 nm and a height of approximately 76 nm.•ATS-NC exhibited a large surface area ∼ 251 m2/g and a pore volume around 0.2 cm3/g.•ATS-NC displayed a larger pKa ∼ 10.3 at 553 nm.•The rapid response time of ATS-NC was observed to be around 0.3 s against pH 12, significant for sensing applications. 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 nanostructure, uniform particles distribution, and crystallite size of 4 nm, roughness of around 19 nm, and thickness ∼ 76 nm. ATS-NC exhibited large surface area ∼ 251 m2/g and a pore volume around 0.2 cm3/g. ATS-NC displayed a larger pKa (negative log of the acid dissociation constant) ∼ 10.3 compared to TSNC (∼ 10) and TNPs (∼ 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. [Display omitted]