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The nickel-doped titanium dioxide nanotubes were prepared by Sol-gel and hydrothermal method and used to photodecompose methylene blue (MB) in liquid phase under visible light irradiation. The anatase-type titania nanotubes were shown to be hollow scrolls with outer diameter of about 10–15 nm and length of several hundred nanometers. The photocatalytic properties of Ni-doped titanium dioxide nanotubes and nanopowders were studied by degrading of MB. The results show that appropriate content of nickel can effectively enhance the photocatalytic activity of titanium dioxide nanotubes. [ABSTRACT FROM AUTHOR]

TiO2 hollow structures have important applications in high performance lithium ion batteries and efficient photocatalysis. In contrast to the conventional synthesis routes where various soft or hard templates are usually put into use, the direct growth of uniform TiO2 hollow nanocrystals is presented. The growth mechanism, lithium ion battery performance, and photocatalytic activity of the resultant TiO2 hollow nanocrystals are thoroughly investigated. TiO2 hollow nanocrystals can be synthesized through a mechanism analogous to the nanoscale Kirkendall effect. The hollow structure results in highly active photocatalysis, high rate capability, and stable cycling. [ABSTRACT FROM AUTHOR]

[Display omitted] Regulating electronic structure and enriching active sites of photocatalysts are effective strategies to promote hydrogen evolution. Herein, a unique Ni x Cd 1-x S-Ni0 photocatalyst, including the surface nickel (Ni) doping and atomic Ni0 anchoring sites, is successfully prepared by Ni2+ ions exchange reaction (Ni 2+ + CdS → Ni x Cd 1- x S) and in-situ photo-induction of Ni0 (N i 2 + + N i x C d 1 - x S → h ν N i x C d 1 - x S - N i 0) , respectively. As to Ni doping, the Ni replaced cadmium (Cd) atoms introduce hybridized states around the Fermi level, modulating the electronic structure of adjacent S atoms and optimizing the photocatalytic activity of sulfur (S) atoms. Besides, photogenerated Ni0 atoms, anchored on unsaturated S atoms, act as charge transfer bridges to reduce Ni2+ ions in the solution to Ni clusters (N i x C d 1 - x S - N i 0 → n e - N i x C d 1 - x S - N i). Subsequently, the displacement reaction of Ni clusters with protons (H+) spontaneously proceeds to produce hydrogen (H 2) in an acidic solution (N i x C d 1 - x S - N i → 2 H + H 2 ↑ + N i 2 + + N i x C d 1 - x S - N i 0). The equilibrium of photo-deposition/dissolution of Ni clusters realizes the construction of dynamic active sites, providing sustainable reaction centers and enhancing surface redox kinetics. The Ni x Cd 1-x S-Ni0 exhibits a high hydrogen evolution rate of 428 mmol·h−1·g−1 with a quantum efficiency of 75.6 % at 420 nm. This work provides the optimal S electronic structure for photocatalytic H 2 evolution and constructs dynamic Ni clusters for chemical replacement reaction. This work provides the optimal S electronic structure for photocatalytic H 2 evolution and constructs dynamic Ni clusters for displacement reaction, opening a dual pathway for efficient water reduction. [ABSTRACT FROM AUTHOR]

• The surface S-vacancies acted as an electronic reservoir and enriched electrons. • The amorphous carbon in the nanocomposite was employed as photo-sensitizers. • The S-vacancies and the carbon enhanced the photo-absorption and photo-responsibility. Carbon -MoS 2−x @CdS (C-MoS 2−x @CdS) core-shell nanostructures with controlled surface sulfur (S) vacancies were prepared via a glucose assisted hydrothermal growth method. The glucose acted as a reducing agent of C-MoS 2−X to partially reduce Mo4+ ions to Mo3+ and served as a carbon source to insert the amorphous carbon into the layered MoS 2−X simultaneously. The presence of Mo3+ result in the surface S-vacancies, which can provide more additional active sites and enhance the photocatalytic performance. Moreover, the inserted carbon in layered MoS 2−X enhanced the electron mobility and decreased the resistance electron transfer. Density functional theory (DFT) calculation confirmed that the surface S-vacancies and the amorphous carbon increase the projected density of states at the conduct band edge, which could enhance the photo-absorption and photo-responsibility. The result is consistent with the photocatalytic H 2 production experiment. C2-10%MoS 2−x @CdS presented a high H 2 evolution rate of 61,494 μmol h−1 g−1 under visible light irrigation (λ ≥ 420 nm), which is 1.98 times and 158 times higher than that of sample without S-vacancies (10%MoS 2 @CdS) and pure CdS, respectively. [ABSTRACT FROM AUTHOR]