Visible-light-driven g-C3N4/Ti3+-TiO2 photocatalyst co-exposed {001} and {101} facets and its enhanced photocatalytic activities for organic pollutant degradation and Cr(VI) reduction

Novel g-C3N4/Ti3+-TiO2 photocatalyst co-exposed {0 0 1} and {1 0 1} facets of TiO2 was synthesized via a hydrothermal-sonication assisted strategy. The photocatalytic activities of the as-obtained photocatalyst were evaluated by the degradation of rhodamine B (RhB) and the reduction of Cr(VI) under visiblelight irradiation. It was found that the g-C3N4/Ti3+-TiO2 composites with 6 wt% g-C3N4 exhibited the highest visible-light photocatalytic efficiency, which is also higher than the pure g-C3N4 and Ti3+-TiO2. A possible photocatalytic mechanism was discussed on the basis of the theoretical analyses and scavenger experiments. Results show that holes (h(+)) and superoxide anions (center dot O-2(-)) reactive species participated in the degradation of RhB solution over the g-C3N4/Ti3+-TiO2 composites. The enhanced photocatalytic activities of g-C3N4/Ti3+-TiO2 composites can be attributed to the wide optical adsorption of g-C3N4 and Ti3+ as well as the effectively separation and transportation of photo-generated electrons and holes pairs, which was resulted from the surface heterojunction between the g-C-3 N-4 and Ti3+-TiO2 nanosheets co-exposed {1 0 1} and {0 0 1} facets of anatase TiO2. (C) 2015 Elsevier B.V. All rights reserved.