Formation of predominant interstitial N–TiO2 using physical preparation under microwave irradiation for reactive red 4 dye removal

• Published in: Desalination and Water Treatment
• Main Author: Azami M.S.; Nawawi W.I.; Shukri D.S.M.
• Format: Article
• Language: English
• Published: Desalination Publications 2017
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85037044126&doi=10.5004%2fdwt.2017.21496&partnerID=40&md5=bb3bfb5fb5d5204c4aecbd5efcde4c32

Interstitial nitrogen titanium dioxide (N–TiO2) has been synthesized from solid-state microwave irradiation of commercial TiO2 (P25) and urea, which is in contrast to other solid-state methods that give substitutional N–TiO2. N–TiO2 was characterized by powder X-ray diffraction (XRD), N2-adsorption surface area measurement, Fourier transformed infra-red (FTIR), X-ray photoelectron spectroscopy (XPS) and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). FTIR, XPS and UV-Vis DRS indicate that interstitial doping of N has occurred in the TiO2 lattice. Ti–O–N detected by FTIR at 1,449 cm–1 contributed to the N–O bond. There is no C=O bond in N–TiO2 showing that urea was completely decomposed in modified TiO2. This N–O bond is also proved by XPS on deconvolution peaks detected at 404.8 and 531.5 eV in N 1s and O 1s, respectively. UV-Vis DRS analysis revealed the formation of N 2p state ca. 0.12 eV above valence band in N–TiO2 and it is almost similar to characteristic of substitutional N–TiO2. Thus, the combination of substitutional and interstitial called interstitial N 2p is suggested in our prepared N–TiO2 sample. The photocatalytic activities of N–TiO2 and pristine TiO2 were compared for the photodegradation of the dye reactive red 4 (RR4) under visible light irradiation from an LED source. Complete bleaching occurred within 60 min using N–TiO2 whereas no photocatalytic degradation was observed using pristine TiO2. © 2017 Desalination Publications. All rights reserved.