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

•Strontium hydroxyapatite,SrHAP degrades p-nitrophenol upon irradiating with 365 nm•5 mol% Ti substitution shifts the absorbance edge of SrHAP from 320 to 340 nm•20 wt% TiO2 loading increases the absorbance edge to 353 nm•Order of activity is noted to be 20 wt% TiO2-SrHAP>5 mol% 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 (∼320 nm) was found to be shifted to longer wavelength in the case of 5 mol%Ti-SrHAP and 20 wt% TiO2-SrHAP. The photodegradation of p-nitrophenol studied using 365 nm UV source showed the photocatalytic activity trend 20 wt%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.

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