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Taking advantage of Ni2+ etching on Co-ZIF-L, NiCo layered double hydroxide (NiCo-LDH) with a leaf-like structure and rough surface was achieved and then employed as the structural template to rationally develop a two-dimensional and core–shell NiCo-LDH/ZnIn2S4 composite. Owing to the morphological merits as well as the tight interfacial contact and enhanced contact area between NiCo-LDH and ZnIn2S4 (ZIS), the obtained NiCo-LDH/ZIS favorably enables the interfacial electron transfer to solve the inherent fast photoinduced electron and hole recombination issue of ZIS. Benefiting from this, NiCo-LDH/ZIS with the optimized NiCo-LDH content displayed a high photocatalytic Cr-(VI) reduction efficiency and was able to reduce 30 mg/L Cr-(VI) within only 3 min under visible light, making it a very promising photocatalyst to treat polluted water containing Cr-(VI). [ABSTRACT FROM AUTHOR]

A novel and highly efficient photocatalyst of Cd 0.5 Zn 0.5 S@ZIF-8 nanocomposite has been developed by a facile self-assembly strategy. This is the first report on the application of Cd x Zn 1−x S and metal-organic framework (MOF) nanocomposite as photocatalysts for the reduction of Cr(VI). The resulting Cd 0.5 Zn 0.5 S@ZIF-8 exhibited higher photocatalytic activity than that of pristine Cd 0.5 Zn 0.5 S and ZIF-8. Particularly, the CZS@Z60 composite with 60 wt% of ZIF-8 exhibited a photocatalytic activity that is about 1.6 times as high as that of Cd 0.5 Zn 0.5 S. The dominant reason for the improved photocatalytic reduction potential is proved to be the newly-formed interfacial S Zn bonds that firmly connect Cd 0.5 Zn 0.5 S and ZIF-8 and substantially improve the separation efficiency of photo-excited electrons and holes. The newly-formed chemical bonds are confirmed by XPS analyses, and the prolonged lifetime of photo-excited electrons is evidenced by the electrochemical measurement of photocurrent, which shows that the photocurrent on Cd 0.5 Zn 0.5 S@ZIF-8 is much higher than that of Cd 0.5 Zn 0.5 S and ZIF-8. This study clearly demonstrates that the MOF-based composite nanomaterials hold great promises for applications in the field of environmental remediation and for design of novel photocatalytic materials. [ABSTRACT FROM AUTHOR]

The delicate design of photocatalyst monoliths is of great significance for the practical applications of artificial photocatalysis. An in-situ synthesis to prepare ZnIn 2 S 4 /cellulose foam was developed. Cellulose is dispersed in a highly concentrated ZnCl 2 aqueous solution to prepare Zn2+/cellulose foam. Zn2+ ions are pre-anchored by hydrogen bonds on cellulose and become in-situ sites for synthesizing ultra-thin ZnIn 2 S 4 nanosheets. This synthesis method makes ZnIn 2 S 4 nanosheets and cellulose tightly bound and prevents ZnIn 2 S 4 nanosheets from stacking in multiple layers. As a proof of concept, the prepared ZnIn 2 S 4 /cellulose foam exhibits a favorable performance for photocatalytic reduction of Cr(VI) under visible light. By adjusting the concentration of zinc ions, the optimal ZnIn 2 S 4 /cellulose foam is capable to completely reduce Cr(VI) in 2 h and the photocatalytic activities show no decrease after 4 cycles. This work could inspire people to build floating cellulose-based photocatalysts via in-situ synthesis. [Display omitted] [ABSTRACT FROM AUTHOR]

MIL-101(Cr)@ZnIn 2 S 4 hierarchical heterojunction was delicately designed and fabricated through the in-situ growth of ZnIn 2 S 4 on MIL-101 and electrostatic self-assembly. It is affirmed that the Cr–S interface bonding between MIL-101 and ZnIn 2 S 4 in their composite was established based on the characterization results of X-ray photoelectron spectroscopy, Raman and zeta potential. Thus, a high-speed channel for charges transfer is offered due to the Cr–S bond, intimate interface contact and hierarchical structure of MIL-101@ZnIn 2 S 4 , which largely inhibits the recombination of photo-induced charge carriers and promises a remarkable photocatalytic activity. Choosing visible-light-driven reduction of Cr(VI) as a model, the optimal MIL-101@ZnIn 2 S 4 sample can reduce 95% of Cr(VI) within 30 min, corresponding to a rate constant of 0.107 min−1, which is 2.9-fold compared with blank ZnIn 2 S 4 counterpart (MIL-101 has a negligible performance). Additionally, a conspicuous apparent quantum yield of 9.7% can be achieved at a wavelength of 420 nm. Eventually, to reinforce the practicability of MIL-101@ZnIn 2 S 4 , the composite powders were manufactured as aerogels utilizing bacterial cellulose as a substrate. The MIL-101@ZnIn 2 S 4 aerogel still exerts an enviable performance for photocatalytic reduction of Cr(VI) and stability. This work could inspire the material design and environmental remediation based on MOFs. [Display omitted] • MIL-101@ZnIn 2 S 4 hierarchical heterojunction with Cr–S bonds was delicately designed. • A high-speed channel for charges transfer is presented over MIL-101@ZnIn 2 S 4. • Efficiently photocatalytic reduction of Cr(VI) is achieved over MIL-101@ZnIn 2 S 4. • Aerogel was prepared from powder to improve the practicability of MIL-101@ZnIn 2 S 4. [ABSTRACT FROM AUTHOR]

Ultrathin ZnIn 2 S 4 (ZIS) nanosheets were coated on g-C 3 N 4 (CN) nanotubes to form CN@ZIS heterojunction as a high-performance photocatalyst for Cr(VI) reduction. Well-dispersed ZIS nanosheets on CN nanotubes favor the better utilization of light and the hierarchical pores promote the mass diffusion. Additionally, such in-situ growth of ZIS on CN nanotubes enables the formation of intimate interfacial contact between them and the obtained CN@ZIS displays a low recombination rate of photo-generated electron-hole pairs compared to the pristine CN and ZIS. Benefiting from these structural and compositional advantages, CN@ZIS exhibits a satisfactory photocatalytic Cr(VI) reduction efficiency and can reduce 30 mg/L Cr(VI) within 10 min (catalyst loading: 1 mg/mL) under visible-light irradiation. Such excellent performance makes CN@ZIS great potential in photocatalysis. [Display omitted] • ZnIn 2 S 4 nanosheets are grown on g-C 3 N 4 nanotube to form CN@ZIS heterojunction. • CN@ZIS exhibits structural and compositional advantages. • CN@ZIS exhibits excellent photocatalytic Cr(VI) reduction performance. [ABSTRACT FROM AUTHOR]