Investigation of photocatalytic activity of pure strontium hydroxyapatite and its Ti-substituted and TiO2 loaded forms

• Published in: Applied catalysis. A, General Vol. 506; pp. 100 - 108
• Main Authors: Gangarajula, Yuvaraj, Kedharnath, Rachakonda, Gopal, Buvaneswari
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.10.2015
• Subjects: p-nitrophenol; Photocatalyst; photodegradation; Powder XRD; Strontium hydroxyapatite; Powder XRD; Strontium hydroxyapatite; p-nitrophenol; photodegradation; Photocatalyst
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2015.08.032

[Display omitted] •Strontium hydroxyapatite,SrHAP degrades p-nitrophenol upon irradiating with 365nm•5mol% Ti substitution shifts the absorbance edge of SrHAP from 320 to 340nm•20wt% TiO2 loading increases the absorbance edge to 353nm•Order of activity is noted to be 20wt% TiO2-SrHAP>5mol% Ti-SrHAP>SrHAP. Photocatalytic activity of Strontium hydroxyapatite (SrHAP) was tested taking the degradation of p-nitrophenol (pnp) as a model reaction and its activity was compared with that of modified SrHAP (Ti4+ Substituted SrHAP and TiO2 loaded SrHAP). The compounds were synthesized by reflux method and characterized by powder XRD, FT-IR, SEM, TEM, UV–vis DRS and BET surface area analyses. Absorption edge of SrHAP (∼320nm) was found to be shifted to longer wavelength in the case of 5 mol%Ti-SrHAP and 20wt% TiO2-SrHAP. The photodegradation of p-nitrophenol studied using 365nm UV source showed the photocatalytic activity trend 20wt%TiO2-SrHAP>Ti-SrHAP>SrHAP. Photodegradation intermediates were identified by UV–vis and HRLC-MS analysis and possible degradation pathways were proposed. Photocatalytic degradation of pnp catalyzed by SrHAP and TiO2 loaded SrHAP followed hydroquinone route whereas, the process catalyzed by Ti4+ substituted SrHAP followed catechol route.