Removing Cr (VI) in water via visible-light photocatalytic reduction over Cr-doped SrTiO3 nanoplates

It is crucial to develop a high-efficiency visible-light responsive photocatalyst for settling the increasing contamination stemmed from toxic heavy metal ions in wastewater. In this study, Cr-doped SrTiO3 (CrSTO) nanoplates were synthesized by a facile one-pot solvothermal method with ethylene glycol as both the solvent and morphology controller. The resultant CrSTO nanoplates are about 100 nm in size and 20 nm in thickness, which are composed of SrTiO 3 nanocrystals about 19 nm in diameter. Furthermore, they possess the mesopore 3.0 nm in size, endowing their much higher specific surface area than the commercial SrTiO3 particles. The Cr element is doped into the crystal lattice of SrTiO3 by the substitution of Cr3+ for Sr2+, which enables the absorption edge redshift to the visible light region, thus elevating the visible-light absorption capability. In addition, the CrSTO-0.9 nanoplate with 0.9% Cr element content exhibits the highest photocatalytic performance for the Cr(VI) reduction under visible light irradiation, which can reduce nearly all Cr(VI) within 3.5 h and preserve the excellent stability after six recycles. This kind of CrSTO nanoplates may serve as a potential and promising photocatalyst for efficient Cr(VI) removal in wastewater. (C) 2018 Elsevier Ltd. All rights reserved.