Constructing TiO2 nanoparticles patched nanorods heterostructure for efficient photodegradation of multiple organics and H2 production

Morphology and exposed facets controlled synthesis of TiO2 has attracted numerous interests due to their fascinating shape-dependent photocatalytic activity, while it still remains in a great challenge to construct TiO2 nanocrystals with surface heterojunction. Here we innovatively constructed a heterostructure of TiO2 nanoparticles patched nanorods (i.e., NP/NR), where the NP and NR were predominately enclosed with the {101} and {100} facets, respectively. Since the highly dispersed nanoparticles (smaller than 10 nm) were closely contacted with nanorods and their electronic band structures are mismatched, it is very likely to form a NP-{101}/NR-{100}surface heterojunction, which significantly facilitates the charge separation and transfer. The ratio of NP to NR is an important factor to govern the NP dispersion, the contact with NR, and the charge separation efficiency, thus determining their photocatalytic activity. Compared with the NP and NR alone, NP0.5/NR0.5 has the optimum ratio and shows an excellent cycling capability for methyl orange degradation (99% retention over 6 cycles) and superior activity for both the photodegradation of multiple organics (2 times faster) and water splitting to H-2 (over 10 times enhancement). A possible charge transfer mechanism on NP-{101}/NR-{100} surface heterojunction has also been proposed to understand the relationship between materials structure and performance. Together with the mechanism study, the nanostructure innovation will advance the development of functional materials for renewable energy and sustainable environment. (C) 2016 Elsevier B.V. All rights reserved.