Enhanced performance of TiO2/reduced graphene oxide doped by rare-earth ions for degrading phenol in seawater excited by weak visible light

La3+- or Yb3+-doped TiO2 supported on the surface of reduced graphene oxide were fabricated by adsorbed-layer nanoreactor synthesis (ANS) coupling with a solvothermal treatment to extend photocatalysis application in the advanced treatment of simulated wastewater with high salt concentration. Results showed that La3+ or Yb3(+) could distribute in the TiO2 lattice, only in ANS preparation with graphene oxide as the carrier, to replace Ti4+ during the solvothermal treatment, thus introducing TiO2 mixed-crystal and heterojunction structures in the catalysts. La3+ or Yb3+ caused lattice distortion structures and anionic vacancies in the TiO2 lattice. The anionic vacancies (oxygen vacancies) might generate Ti3+ in catalysts, thus enhancing visible-light response, due to impurity levels introduced by La3+ or Yb3+. As the strong adsorption capability of the catalyst for phenol was not interfered by salt ions in the simulated wastewater, the catalysts could efficiently degrade phenol. The highest removal rate of phenol was approximately 90%. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.