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Designing high‐efficiency photocatalysts with high charge separation and rapid charge transfer still a challenge. Herein, highly effective g‐C3N4/NH2–UIO‐66 (CNU) hybrids are developed using an engineered ZrN bond between the two components. The formation of the ZrN bond provides an electron transfer pathway between the conduction band (CB) of g‐C3N4 (CN) and Zr centers, which shortens the carrier migration distance, greatly enhancing the separation efficiency of photogeneration carriers. The as‐prepared CNU shows an outstanding performance for photocatalytic reduction of Cr(VI) under visible light irradiation due to the rapid charge carrier interfacial transfer. This work provides a promising strategy for the design of efficient photocatalysts and helps to establish an effective and sustainable method for removing Cr(VI) under ambient conditions. [ABSTRACT FROM AUTHOR]

Mesoporous titanium nitride (TiN) microspheres with tunable chamber structures were synthesized through NH3 nitridation of organotitania obtained via solvothermal alcoholysis. Owing to high content of organic species in organotitania, which stabilized the original structure and also promoted the nitridation at low temperature, TiN duplicated the solid, yolk-shell, and hollow chambers of organotitania in NH3 nitridation and also formed the mesoporous structure after removing organic species. During visible light-induced photocatalytic water splitting, the yolk-shell TiN demonstrated a higher H2 evolution efficiency than the solid, hollow, and crushed TiN; the yolk-shell TiN obtained through N2 nitridation; and other semiconductor photocatalysts reported so far without the aid of noble metals. This could be attributed mainly to the narrow energy band gap for absorbing visible light, high surface area, and excellent electrical conductivity, which facilitated light harvesting, reactant adsorption, and photoelectron-hole separation to suppress their recombination. Moreover, it could be easily recycled and thus used repetitively. [ABSTRACT FROM AUTHOR]

In order to develop efficient photocatalysts, great efforts have been made to reduce hexavalent chromium to trivalent chromium. The photocatalytic efficiency of this reduction depends largely on the adsorption and diffusion of hexavalent chromium ions on the surface of the photocatalyst. In this paper, polyaniline-TiO 2 composite can effectively improve the photocatalytic reduction performance and stability of hexavalent chromium ion. The effect of polyaniline (PANI) thickness on Cr(VI) activity and stability of photocatalytic reduction was studied by adjusting the content of PANI on Mesoporous TiO 2 (MT) surface. Under the irradiation conditions, the reaction results showed that the reduction rate was 100%, and the maximum reaction rate reached 0.62 min−1 when the PANI modification was 3.0%. Moreover, the results showed that the reduction performance remained 100% after ten cycles. The main reason is that the PANI modified on the surface of TiO 2 is rich in positively charged amino group, which can efficiently adsorb the reactant Cr(VI), and make the product Cr(III) leave the reaction interface quickly, thus ensuring the performance of photocatalyst. [ABSTRACT FROM AUTHOR]

• Nanostructured [Mo 3 S 13 ]2−/TiO 2 composites were synthesized. • [Mo 3 S 13 ]2−/TiO 2 composites exhibited higher photocatalytic activity than Pt/TiO 2. • [Mo 3 S 13 ]2− could enhance the photo-induced charges separation efficiency. • [Mo 3 S 13 ]2−/TiO 2 photocatalysts coated on non-woven fabrics showed obvious promotion on the degradation of acetone. Improving the photocatalytic efficiency of commercial TiO 2 has important significance for practical application of TiO 2 based photocatalysts. A novel photocatalyst [Mo 3 S 13 ]2−/TiO 2 was fabricated by combining [Mo 3 S 13 ]2− with commercial TiO 2 by an impregnation method. This composite photocatalyst presented a remarkable enhancement on photocatalytic mineralization of acetone in comparison with commercial TiO 2. The optimum loading amount of [Mo 3 S 13 ]2− was 1.7wt%, which is more efficient than the Pt/TiO 2 (1.5wt%). Electrochemical impedance spectroscopy (EIS) showed the smooth electron transfer pathway in [Mo 3 S 13 ]2−/TiO 2 composite, facilitating the photo-charges separation during the photocatalysis process. Reactive oxygen species scavenging test illustrated that superoxide radical (O 2 −), hydroxyl radical (OH) and photo-induced hole (h+) were all contributing to the acetone degradation. The [Mo 3 S 13 ]2−/TiO 2 photocatalyst was deposited on non-woven fabrics which showed obvious promotion on the photocatalytic degradation of acetone in comparison with pristine commercial TiO 2. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Carbon dots (CD) was coupled with TiO 2 mesocrystals, where CD displayed both the electron collectors and the active sites. • The positive charges on the CD/MT surface favored the selective adsorption of Cr(VI) and rapid desorption of Cr(III). • The selective adsorption-desorption has an obvious promotion on the photocatalytic reduction of Cr(VI) and recyclability. • The CD/MT exhibited activity about 5.4 times higher than the pure TiO 2 mesocrystals during photoreduction of Cr(VI). • It provides a simple and effective adsorption-photoreduction-desorption mechanism for the photo-reduction of Cr (VI). Abstract The photocatalytic reduction efficiency of hexavalent chromium (Cr 2 O 7 2− (Cr(VI)) is suffering from high recombination of photoinduced charges, poor adsorption capacity of Cr(VI), and slow desorption of product trivalent chromium (Cr3+ (Cr(III))) from photocatalyst surface. In this work, carbon dots (CDs) was coupled with TiO 2 mesocrystals (MT), where CDs displayed both the electron collectors and the active sites. During photoreduction of Cr(VI), the as-prepared CD/MT exhibited activity about 5.4 times higher than the pure TiO 2 mesocrystals. The positive charges on the CD/MT surface favored the selective adsorption of Cr(VI) and rapid desorption of Cr(III), which has an obvious promotion on the photocatalytic reduction of Cr(VI) and retention of photoreduction activity. Meanwhile, the CDs coupled on TiO 2 mesocrystals facilitated the separation of photogenerated charges. This work provides a simple and effective adsorption-photoreduction-desorption mechanism for the photocatalytic reduction of Cr(VI). [ABSTRACT FROM AUTHOR]

The selective adsorption of hexavalent chromium (Cr 2 O 7 2− (Cr(VI))) and the desorption of trivalent chromium (Cr 3+ (Cr(III))) at the surface of photocatalysts are very important factors in determining the photocatalytic reduction activity of Cr(VI). Here, a homogeneous anchoring of hydroxyl groups on TiO 2 was achieved via a simple soaking method in alkaline solution. The increase of surface hydroxyl groups was confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectra (FTIR). Moreover, the zeta potential analysis revealed the positive charged TiO 2 surface in the acid system shown a significant improvement. The surface positive charges had the selective adsorption for Cr(VI) and desorption for Cr(III). Further experimental results revealed that such selective adsorption process played important roles in the photocatalytic reduction of Cr(VI). Finally, a process of selective adsorption/desorption promoted photocatalytic reduction of Cr(IV) was proposed in detail. [ABSTRACT FROM AUTHOR]

CdS quantum dots decorated TiO 2 mesocrystals with exposed (001) facets were synthesized by solvothermal alcoholysis and subsequent ion-exchange. The as-prepared photocatalyst exhibited high activity and selectivity in selective oxidations of various alcohols to their corresponding aldehydes under visible light irradiation. The high photocatalytic efficiency could be ascribed to the CdS quantum dots with enhanced photosensitizing effect and CdS-TiO 2 heterojunction, the mesoporous structure with high surface area, and the exposed (001) facets with high surface energy and large number of oxygen vacancies, which promoted the light-harvesting, photocatalyst activation by visible lights, photoelectron-hole separation, reactant molecule adsorption and activation. Moreover, it also showed strong durability owing to the excellent stability against structural collapse and either CdS leaching or CdS corrosion. [ABSTRACT FROM AUTHOR]