Na2Ti6O13@TiO2 core-shell nanorods with controllable mesoporous shells and their enhanced photocatalytic performance

Abstract In this study, dispersive and free-standing Na 2 Ti 6 O 13 nanorods with diameter of about 500 nm and length of about 10 μm were synthesized by the molten salt method. The Na 2 Ti 6 O 13 @TiO 2 (denoted as TTO) core-shell nanorods were fabricated by a versatile kinetics controlled coating method. The TiO 2 shells were uniform and mesoporous with exposed {101} facets. The thickness of TiO 2 shells can be well controlled by the content of Ti(OC 4 H 9 ) 4 , ranging from 0 nm, 15 nm, 60 nm to 70 nm corresponding to Na 2 Ti 6 O 13 , 0.25-TTO, 0.50-TTO and 0.75-TTO nanorods respectively. The crystalline phases, microstructure, porosity, photoabsorption and photocatalytic performance of all the samples were investigated systematically. The nanoscale heterojunction structure between Na 2 Ti 6 O 13 and TiO 2 , reductive TiO 2 {101} facets and high aspect ratio Na 2 Ti 6 O 13 nanorods resulted in the enhanced photocatalytic performance of TTO nanorods. The optimized thickness of TiO 2 shells were about 60 nm for 0.50-TTO nanorods, which possessed superior BET surface area, optical absorption and photocatalytic performance.