Facile synthesis of ultrafine CuS nanocrystalline/TiO2: Fe nanotubes hybrids and their photocatalytic and Fenton-like photocatalytic activities in the dye degradation

Interface-induced effect and large specific surface area of heteronano-structures are attracting much attentions due to applications in photocatalysis. In this work, ultrafine CuS nanocrystalline/Fe-doped TiO2 nanotubes hybrids were fabricated with facile methods. The effect of the ratio of CuS to Fe-doped TiO2 nanotubes (NTs) on the microstructural, optical and photocatalytic properties of the NTs and hybrids were studied. The NTs showed an actual Fe content of similar to 2.93 at % and an optical bandgap of -3.00 eV. The bandgap of the hybrids were similar to 2.50-2.95 eV decreased with increasing CuS/NTs ratio. The specific surface area of the NTs was similar to 333 m(2) g(-1). Whereas the hybrids showed remarkably larger specific surface area of similar to 794-1100 m(2) g(-1) than the NTs because of well controlled formation process of CuS nanoparticles. The sunlight-excited degradation experiments of malachite green in the water indicated that the photo- and photo-Fenton-like catalytic activity of the hybrids was higher than that of the NTs and increased with increasing CuS/NTs ratio. The quasi-kinetic first-order rate constant was in the range of similar to 0.260-1.181 h(-1) and increased to similar to 3.932-10.597 h(-1) in the present of the H2O2 aqueous solution with a concentration of 20 ml l(-1). The high photocatalytic activity of the hybrids was mainly ascribed to the narrow bandgap, large specific surface area and effective heterojunction. (C) 2016 Elsevier Inc. All rights reserved.