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The construction of a 2D–2D heterostructured composite is an efficient method to improve the photocatalytic hydrogen generation capability under visible light. In this work, simple heat treatment of a mixture of g‐C3N4 and delaminated Ti3C2 was used to prepare a series of d‐Ti3C2/TiO2/g‐C3N4 nanocomposites. The d‐Ti3C2 not only acted as the support layer and resource to glue the anatase TiO2 particles and g‐C3N4 layers together but also served as the fast electron transfer channel to improve the photogenerated charge carriers' separation efficiency. By tuning the g‐C3N4/d‐Ti3C2 mass ratio, heating temperature and soaking time, the d‐Ti3C2/TiO2/g‐C3N4 nanocomposite 4‐1‐350‐1 achieved an excellent H2 evolution rate of 1.62 mmol h−1 g−1 driven by a 300 W Xe lamp with a 420 nm cutoff filter. The heterostructured composite photocatalyst was stable even after 3 cycles, representing excellent potential for the practical application in solar energy conversion. Heterostructured d‐Ti3C2/TiO2/g‐C3N4! The photocatalytic activities of Ti3C2 and g‐C3N4 are critically dependent on the microstructure. A facile heating treatment of the Ti3C2 and g‐C3N4 mixture is used to obtain heterostructured d‐Ti3C2/TiO2/g‐C3N4 nanocomposites (see image). The TiO2 particles and g‐C3N4 nanosheets are glued together by the delaminated Ti3C2 layers, demonstrating excellent performance in visible‐light photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

The graphene-AgVO 3 nanocomposites (GA30) were synthesized by facile one-step chemical-bath method. SEM and TEM images of the synthesized nanocomposites indicate that this method is possible to anchor the AgVO 3 nanoparticles onto the graphene surface. Galvanostatic charge-discharge (GCD) shows that specific capacitance, cycle stability, and rate capability of the supercapacitor device can be enhanced with AgVO 3 incorporation. The GA30 shows a high energy density of 10 Wh/kg at a power density of 25 W/kg as well as a high power density of 2045 W/kg at an energy density of 6 Wh/kg, which are much higher than those of graphene/activated carbon composites (GC30) and previous reported graphene-based composites. The improvement in specific capacitance, cycle stability, energy density and powder density of the graphene would be attributed to the special microstructure with high-rate transportation of both electrolyte ions and electrons due to the incorporation of AgVO 3 . [ABSTRACT FROM AUTHOR]

The ZnO/g-C 3 N 4 nanocomposites were synthesized by a single-step and scalable synthesis method through calcining the mixture of zinc acetate and urea. Two-dimensional shape, porous and carbon-doped microstructure were demonstrated by the SEM, TEM, N 2 adsorption and XPS. ZnO/g-C 3 N 4 nanocomposites were used as a photocatalyst for photodegradation of MB and MO under visible light irradiation. The photocatalytic performance of the porous sheet-like carbon-doped ZnO/g-C 3 N 4 nanocomposites was higher than those of commercial P25, ZnO and g-C 3 N 4 . [ABSTRACT FROM AUTHOR]

In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h + ) and superoxide radicals ( O 2 − ). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • ZnO@G was synthesized using a facile room-temperature method through colloidal coagulation effect. • ZnO@G nanocomposite modified electrode significantly improved the electrochemical sensitivity for Cd2+ and Pb2+ detection in the presence of Bi3+ using anodic stripping voltammetry. • This system was successfully applied for the simultaneous determination of Cd2+ and Pb2+ in real wastewater samples. Abstract Zinc Oxide (ZnO) nanorods were synthesized by using zinc acetate as a precursor via thermal decomposition method and then used to prepare ZnO@G nanocomposite by facile room-temperature approach using a colloidal coagulation effect. The as prepared ZnO@G nanocomposite was applied to modify the working electrode surface in an electrochemical sensor of Cd2+ and Pb2+for the first time. The morphologies of ZnO and ZnO@G nanocomposite were characterized by transmission electron microscopy, that exhibits the nanorod shape with an average diameter of 89 ± 18 nm, uniformly dispersed and intercalated between each G layer. Furthermore, the important factors affecting on the sensor sensitivity, including ZnO@G ratio, ZnO@G concentration, Bi3+ concentration and electrochemical parameters were systematically investigated using square-wave anodic stripping voltammetry. Under the optimal conditions, a linear range was found to be 10–200 μg L−1 and the detection limits were 0.6 and 0.8 μg L-1 for Cd2+ and Pb2+, respectively. Eventually, it was successfully used for the simultaneous detection of Cd2+ and Pb2+ in real wastewater samples and the results corresponded well with a standard inductively coupled plasma-optical emission spectroscopy. [ABSTRACT FROM AUTHOR]

In this study, synthesis of novel binary chitosan-SnO 2 nanocomposites is reported. Different physical and chemical techniques were used to characterize and analyze the characteristics of the chitosan-SnO 2 nanocomposites as photocatalysts. The prepared novel photocatalysts were used to degrade the model dyes such as methyl orange (MO) and rhodamine B (RhB) under different wavelengths (254, 310 and 365 nm) of UV light. The photocatalytic degradation results suggest that the prepared binary chitosan-SnO 2 (50:50) nanocomposite shows superior degradation efficiency compared with pure SnO 2 and binary chitosan-SnO 2 (75:25) nanocomposite owing to its high crystallinity, high surface area, and small particle size. It was also observed that chitosan-SnO 2 (50:50) nanocomposite under different wavelengths (254 nm, 310 nm, and 365 nm) of UV light showed highest photocatalytic degradation of methyl orange and rhodamine B at 365 nm irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanosized CdS decorated TiO 2 @BaTiO 3 core–shell composite was successfully synthesized. • The designed composite removes the shielding effect toward the polarized electric field. • A permanent built-in electric field is formed in BaTiO 3 layer without applied mechanical stress. • The photoexcited charge carriers realize completely spatial separation. • This composite shows an excellent photocatalytic hydrogen activity. Ferroelectrics have the advantage of spatially separating the photogenerated charge carriers via the spontaneous polarized electric field, although the strength of the polarized electric field may suffer from the influence of the electrostatic shielding effect, which could reduce the charge carrier separation without mechanical stress. Herein, we developed a novel CdS decorated TiO 2 @BaTiO 3 core–shell nanocomposite, where the optimal ratio of TiO 2 , BaTiO 3 and CdS are 53.43, 37.37 and 9.20 wt%, respectively, for the best photocatalytic activity. The TiO 2 @BaTiO 3 /CdS nanocomposite reported in this work offers a persistent electric field in the ferroelectric BaTiO 3 shell, due to the limited shielding effect in an asymmetrically polarized field. With the built-in electric field as the driving force, the photogenerated electrons and holes flowed into the CdS surface and the TiO 2 core, respectively, with improved charge separation to participate in water-splitting reactions. The measured charge carrier lifetime of TiO 2 @BaTiO 3 /CdS nanocomposite via transient fluorescence spectrum is 0.42 ns, which is much longer than the TiO 2 (0.25 ns) and TiO 2 @BaTiO 3 (0.31 ns) samples. The TiO 2 @BaTiO 3 /CdS nanocomposite shows an enhanced photocatalytic hydrogen evolution rate of 13.22 mmol/g∙h under visible light illumination with an AQE of 52.50 % at 405 nm monochromatic light. This is much better than their components and binary composites, including TiO 2 /Pt (0.63 mmol/g∙h), CdS (1.23 mmol/g∙h), TiO 2 @BaTiO 3 (0.03 mmol/g∙h), TiO 2 /CdS (0.53 mmol/g∙h), and BaTiO 3 /CdS (2.62 mmol/g∙h). This work provides an effective strategy for the construction of a ferroelectric photocatalyst with much-improved charge separation by the permanent internal electric field. [ABSTRACT FROM AUTHOR]

Colourful dyes are primarily used in the textiles, toys, food, inks, paper and plastics. These dyes are water soluble and contaminate the water. The dyes are not bio-degradable and sustain in the water for long time create diseases like bladder tumour and chromosomal damage. Hence dyes are the major cause of pollution and must be removed from domestic and drinking water. The photocatalysts are energy-less technology for dye degradation and expected to solve clean water problems. Most of the photocatalysts are metal oxides and absorbed in the ultra violet region. But, sun light mostly consists of visible light, hence to use the sunlight effectively the absorption spectrum of the photocatalysts must be tuned to the visible region. Herein, we proposed visible light absorbed new TiO 2 /NiO nanocomposite for methyl orange dye degradation. The integration of NiO modified the TiO 2 nanocomposite UV absorption spectrum into visible light region. The photocatalyst was prepared using mechano-thermal method and characterised using PXRD, TGA, FT-IR, HR-TEM, EDS, UV, PL and DRS methods. The photocatalytic property was explored using the degradation of methyl orange and compared the activity with different time intervals and wide range of pH. Within 60 min of irradiation, 98% of degradation was observed. Similarly, at all pH range more than 50% of degradation was observed, but the best performance (98%) was observed at pH = 7 (neural). Thus, the TiO 2 /NiO nanocomposite catalyst was effective in neutral, acidic and basic polluted water treatment. The synthesized TiO 2 /NiO nanocomposite is tuneable to visible light and degrade the methyl orange dye in all pH range. • TiO 2 -NiO nanocomposite system prepared by new method (sol-gel along with mechano-thermal process). • The formation p-n (TiO 2 -NiO) junction along with Ni3+ states prevents electrons-holes recombination. • The incorporation of NiO generate line defect on the TiO 2 surface. • The presence of Ni3+ and line defect were promoted the visible light activity. [ABSTRACT FROM AUTHOR]