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The binary heterostructured semiconducting visible light photocatalyst of the iron-doped graphitic carbon nitride/bismuth molybdate (Fe-g-C3N4/Bi2MoO6) composite was prepared by coupling with Fe-doped g-C3N4 and Bi2MoO6 particles. In the present study, a comparison of structural characteristics, optical properties, and photocatalytic degradation efficiency and activity between Fe-doped g-C3N4 particles, Bi2MoO6 particles, and Fe-g-C3N4/Bi2MoO6 composite was investigated. The results of X-ray diffraction (XRD) examination indicate that the hydrothermal Bi2MoO6 particles have a single orthorhombic phase and Fourier transform infrared (FTIR) spectroscopy analysis confirms the formation of Fe-doped g-C3N4. The optical bandgaps of the Fe-doped g-C3N4 and Bi2MoO6 particles are 2.74 and 2.73 eV, respectively, as estimated from the Taut plots obtained from UV-Vis diffuse reflectance spectroscopy (DRS) spectra. This characteristic indicates that the two semiconductor materials are suitable for absorbing visible light. The transmission electron microscopy (TEM) micrograph reveals the formation of the heterojunction Fe-g-C3N4/Bi2MoO6 composite. The results of photocatalytic degradation revealed that the developed Fe-g-C3N4/Bi2MoO6 composite photocatalyst exhibited significantly better photodegradation performance than the other two single semiconductor photocatalysts. This property can be attributed to the heterostructured nanostructure, which could effectively prevent the recombination of photogenerated carriers (electron–hole pairs) and enhance photocatalytic activity. Furthermore, cycling test showed that the Fe-g-C3N4/Bi2MoO6 heterostructured photocatalyst exhibited good reproducibility and stability for organic dye photodegradation. [ABSTRACT FROM AUTHOR]

A facile one-pot microwave-assisted synthesis prepared a new noble metal-free heterostructure of In 2 S 3 /In 2 O 3 nanosheets for blue LED-light-induced photocatalytic water splitting. The appropriate InCl 3 concentrations and reaction temperatures can grow the In 2 S 3 /In 2 O 3 nanosheets with higher photocatalytic water splitting for hydrogen production under blue-LED light irradiation. In addition, the optimized In 2 S 3 /In 2 O 3 nanosheets exhibited a higher hydrogen production rate is 618.0 μmolh−1g−1 in seawater without adjusted pH values under blue-LED light irradiation. Furthermore, the reusability of In 2 S 3 /In 2 O 3 nanosheets revealed the gradual increase of photocatalytic hydrogen production efficiency in four cycles. This phenomenon shall be attributed to the reaction of In 2 S 3 /In 2 O 3 nanosheets and seawater to form In 2 S 3 /In 2 O 3 /In(OH) 3 nanosheets, which can improve the recombination of the photogenerated charge carriers and light-harvesting capacity to promote their photocatalytic hydrogen production. [Display omitted] • In 2 S 3 /In 2 O 3 nanosheets were prepared using one-pot microwave-assisted synthesis. • In 2 S 3 /In 2 O 3 nanosheets exhibited higher photocatalytic water or seawater splitting. • In 2 S 3 /In 2 O 3 /In(OH) 3 nanosheets can be synthesized under photocatalytic seawater splitting. • In(OH) 3 can enhance the separation charge carriers and light-harvesting capacity. [ABSTRACT FROM AUTHOR]

A multi-step procedure was effectively employed to synthesize innovative three-dimensional (3D) heterostructures encompassing sodium titanate (Na2Ti3O7) nanowire cores, an intermediate resorcinol–formaldehyde (RF) layer, and outer silver (Ag) nanoparticle sheaths, referred to as Na2Ti3O7@RF@Ag heterostructures. Initially, a one-step hydrothermal technique facilitated the direct growth of single-crystal Na2Ti3O7 nanowires onto a flexible Ti foil. Subsequently, a two-step wet chemical process facilitated the sequential deposition of an RF layer and Ag nanoparticles onto the Na2Ti3O7 nanowires at a low reaction temperature. Optimal concentrations of silver nitrate and L-ascorbic acid can lead to the cultivation of Na2Ti3O7@RF@Ag heterostructures exhibiting heightened surface-enhanced Raman scattering (SERS), which is particularly beneficial for the detection of rhodamine B (RhB) molecules. This phenomenon can be ascribed to the distinctive geometry of the Na2Ti3O7@RF@Ag heterostructures, which offer an increased number of hot spots and surface-active sites, thereby showcasing notable SERS enhancement, commendable reproducibility, and enduring stability over the long term. Furthermore, the Na2Ti3O7@RF@Ag heterostructures demonstrate remarkable follow-up as first-order chemical kinetic and recyclable photocatalysts for the photodecomposition of an RhB solution under UV light irradiation. This result can be attributed to the enhanced inhibition of electron–hole pair recombination and increased surface-active sites. [ABSTRACT FROM AUTHOR]

In this study, a facile and rapid microwave-assisted synthesis method was used to synthesize In2S3 nanosheets, ZnS nanosheets, and ZnIn2S4 nanosheets with sulfur vacancies. The two-dimensional semiconductor photocatalysts of ZnIn2S4 nanosheets were characterized by XRD, FESEM, BET, TEM, XPS, UV–vis diffuse reflectance, and PL spectroscopy. The ZnIn2S4 with sulfur vacancies exhibited an evident energy bandgap value of 2.82 eV, as determined by UV–visible diffuse reflectance spectroscopy, and its energy band diagram was obtained through the combination of XPS and energy bandgap values. ZnIn2S4 nanosheets exhibited about 33.3 and 16.6 times higher photocatalytic hydrogen production than In2S3 nanosheets and ZnS nanosheets, respectively, under visible-light irradiation. Various factors, including materials, sacrificial reagents, and pH values, were used to evaluate the influence of ZnIn2S4 nanosheets on photocatalytic hydrogen production. In addition, the ZnIn2S4 nanosheets revealed the highest photocatalytic hydrogen production from seawater, which was about 209.4 and 106.7 times higher than that of In2S3 nanosheets and ZnS nanosheets, respectively. The presence of sulfur vacancies in ZnIn2S4 nanosheets offers promising opportunities for developing highly efficient and stable photocatalysts for photocatalytic hydrogen production from seawater under visible-light irradiation. [ABSTRACT FROM AUTHOR]

This study synthesized the In(OH) 3 –In 2 S 3 nanosheet via a simple hydrothermal method. The different amounts of In(OH) 3 –In 2 S 3 nanosheet used to synthesize In(OH) 3 –In 2 S 3 –Cu 2 O composite by a wet chemical method. FESEM, FETEM, XRD, XPS, BET, UV–vis DRS, and PL spectroscopy characterized the In(OH) 3 –In 2 S 3 –Cu 2 O composite. Compared with In(OH) 3 –In 2 S 3 nanosheet, In(OH) 3 –In 2 S 3 –Cu 2 O composite can exhibit the synergistic effects of higher specific surface area, higher light-harvesting capacity, and accelerating the separation and migration of photogenerated charge carriers. In addition, In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber was fabricated via a facile electrospinning process at the different amounts of In(OH) 3 –In 2 S 3 nanosheet. The manufacturing process offers many advantages, such as simplicity, low temperature, and without templates. The effect of operational parameters (such as the reaction conditions of photocatalysts, pH values, sacrificial reagents, and light sources) on the photocatalytic hydrogen production of In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber was investigated. The results indicate that the appropriate reaction conditions of In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber can reveal higher efficient photocatalytic water splitting than commercial TiO 2 or ZnO nanofiber under blue light LED excitation. Furthermore, In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber can provide a simple fabrication process, high photocatalytic activity, and high reusability shall be beneficial for the practical application of photocatalytic hydrogen production. [Display omitted] • In 2 S 3 –In(OH) 3 –Cu 2 O nanofiber (NF) was prepared using the electrospinning method. • In 2 S 3 –In(OH) 3 –Cu 2 O NF exhibited enhanced photocatalytic activity for H 2 evolution. • The HER of In 2 S 3 –In(OH) 3 –Cu 2 O NF is 14.5 times higher than In(OH) 3 NF. • Cu 2 O nanoparticles can enhance charge-carries separation and transfer efficiency. • The mechanism for the photocatalytic H 2 production with In 2 S 3 –In(OH) 3 –Cu 2 O was explained. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4), W-doped BiVO4 (BiVO4:W), and Mo-doped BiVO4 (BiVO4:Mo) nanoparticles were synthesized at pH = 4 using a green hydrothermal method. The effects of 2 at% W or Mo doping on the microstructural and optical characteristics of as-prepared BiVO4 nanoparticles and the effect of combining particle morphology modification and impurity dopant incorporation on the visible-light-derived photocatalytic degradation of dilute Rhodamine B (RhB) solution are studied. XRD examination revealed that these obtained BiVO4-based nanoparticles had a highly crystalline and single monoclinic phase. SEM and TEM observations showed that impurity doping could modify the surface morphology, change the particle shape, and reduce the particle diameter to enlarge their specific surface area, increasing the reactive sites of the photocatalytic process. XPS and FL measurements indicated that W- and Mo-doped nanoparticles possessed higher concentrations of oxygen vacancies, which could promote the n-type semiconductor property. It was found that the BiVO4:W and BiVO4:Mo powder samples exhibited better photocatalytic activity for efficient RhB removal than that shown by pristine BiVO4 powder samples under visible light illumination. That feature can be ascribed to the larger surface area and improved concentration of photogenerated charge carriers of the former. [ABSTRACT FROM AUTHOR]

ZnO nanowires and nanowalls can be fabricated on the glass substrate with a ZnO seed film and low-cost aluminum (Al) foil by the aqueous solution method (ASM), respectively. The different concentrations of ZnO precursors can use to control the densities of ZnO nanowalls. In addition, FESEM, FETEM, EDS, XRD, XPS, and CL were used to evaluate the characteristics of ZnO nanowalls. The ZnO nanowalls exhibited higher photocatalytic efficiency (99.4%) than that of ZnO nanowires (53.3%) for methylene blue (MB) degradation under UVC light irradiation at the ZnO precursors of 50 mM. This result is attributed to ZnO nanowalls with Al-doped, which can improve the separation of photogenerated electron-hole pairs for enhanced photocatalytic activity. In addition, ZnO nanowalls can also reveal higher photocatalytic activity for the degradation of tetracycline capsules (TC) rather than commercial ZnO nanopowder under UVC light irradiation. The superoxide and hydroxyl radicals play essential roles in the degradation of MB and TC solutions by the radical-trapping experiment. Furthermore, the ZnO nanowalls exhibit excellent recycling and reuse capacity for up to four cycles for the degradation of MB and TC. This study highlights the potential use of ZnO nanowalls directly grown on commercial and low-cost Al foil as noble metal-free photocatalysis. [ABSTRACT FROM AUTHOR]

We demonstrate the synthesis of heterostructured photocatalysts that the double-sided plasmonic Au nanoparticles have been deposited on the Cu-doped ZnO/ZnO heterostructures by a facile ion sputtering method. The resultant quaternary Cu-doped ZnO/Au/ZnO/Au heterostructures exhibit excellent photocatalytic activity in the photodegradation of rhodamine 6G under 10 W UV light irradiation, which is much higher than Cu-doped ZnO/ZnO heterostructures. Moreover, the Cu-doped ZnO/Au/ZnO/Au heterostructures can be reused for degradation of R6G during a five-cycle experiment without significant decrease in the photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

Single-crystalline Cu-doped ZnO nanowires have been directly grown on the flexible brass mesh substrates in a large-scale by using a one-step annealing process under ambient condition. Cu-doped ZnO nanowires on the dense brass mesh substrates can provide a higher surface-to-volume ratio and better stability against aggregation, which exhibit excellent photocatalytic activity rather than the different amounts of commercial TiO 2 nanopowders under a 10 W UV light irradiation. In addition, Cu-doped ZnO nanowires are also revealed a good dynamic photocatalytic efficiency, which shall be beneficial in industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

• Multistep processes can successfully synthesize the TiO 2 /NiS/Pt nanofiber (NF). • The TiO 2 /NiS/Pt NF exhibited enhanced photocatalytic activity for H 2 evolution. • The HER over the TiO 2 /NiS/Pt NF has 292 times increase over pure TiO 2 NF. • TiO 2 /NiS/Pt NF can lead to carriers' higher separation and transfer efficiency. • TiO 2 /NiS/Pt NF can provide practical application in seawater splitting. The porous TiO 2 nanofiber has been synthesized via facile electrospinning and thermal annealing. Furthermore, the intermediate layer of NiS and Pt nanoparticles can be sequentially deposited on the porous TiO 2 nanofiber to form hierarchical core-shell TiO 2 /NiS/Pt nanofiber through wet-chemical and self-assembly processes. Compared with the TiO 2 (16 µmolh−1g−1 L−1) nanofiber and TiO 2 /NiS nanofiber (54 µmolh−1g−1 L−1), TiO 2 /NiS/Pt nanofiber (4411 µmolh−1g−1 L−1) revealed remarkably photocatalytic activity for hydrogen evolution from water under visible light excitation. The significant enhancement in photocatalytic activity over the TiO 2 /NiS/Pt nanofiber could be attributed to enhanced visible light absorption and the separation of photogenerated electrons and holes. Furthermore, reusability experiments prove that TiO 2 /NiS/Pt nanofiber exhibits excellent stability for the long-term photocatalytic process. In addition, TiO 2 /NiS/Pt nanofiber can also use photocatalytic hydrogen production under different water bases. Therefore, this study provides a promising strategy to develop a novel heterostructure photocatalyst for highly efficient energy conversion. [Display omitted] [ABSTRACT FROM AUTHOR]

The ZnO nanorods have been grown on the cotton threads with ZnO seed layer by an aqueous chemical growth method at the low reaction temperature. The ZnO nanorods can provide a good geometric structure to deposit Pt nanoparticles with uniform size by a facile ion sputtering method. The photocatalytic activity of the different lengths of cotton threads with ZnO nanorods were evaluated in the photocatalytic degradation of rhodamine 6G by a 10 W UV light irradiation. The ZnO/Pt core-shell nanorods revealed much higher photodegradation efficiency than ZnO nanorods or commercial TiO 2 nanopowders, which improved the separation of photogenerated electrons and holes. Furthermore, the reusability test can demonstrated that the ZnO/Pt core-shell nanorods on the cotton threads still maintained high photocatalytic activity over five cycles. The ZnO/Pt core-shell nanorods provide a facile, low cost, high surface-to-volume ratio, high photocatalytic efficiency, and high reusability, which shall be also promising in the decomposition of environment pollutants and reusing of wastewater treatment. [ABSTRACT FROM AUTHOR]

The complex ZnO/ZnS nanocable and nanotube arrays have been grown on the silicon or glass substrates with ZnO nanowire arrays by an aqueous chemical growth method at the low reaction temperature. The concentration of ZnS precursor and reaction time can be used to control the different sizes and shell thicknesses of complex ZnO/ZnS nanocable and nanotube arrays. The complex ZnO/ZnS nanocable and nanotube arrays exhibit very prominent blue emission and week UV emission from ZnS defect and ZnO band gap in the cathodoluminescence spectrum, respectively. The photocatalytic activity of the different complex ZnO/ZnS nanocable and nanotube arrays were evaluated in the photocatalytic degradation of methylene blue under 10 W UV light irradiation. The complex ZnO/ZnS nanocable and nanotube arrays revealed much higher photodegradation efficiency than ZnO nanowire arrays. This result is attributed to increase the separation of photogenerated electron–hole pairs on the surface of ZnO/ZnS nanocable and the surface-to-volume ratio on the ZnS nanotube. The photocatalytic mechanism under UV light irradiation was proposed. Furthermore, the reusability test can demonstrated that the complex ZnO/ZnS nanocable and nanotube arrays still maintained high photocatalytic activity over ten cycles. The complex ZnO/ZnS nanocable and nanotube arrays provide a facile, low cost, high surface-to-volume ratio, high photocatalytic efficiency, and high reusability, which shall be also promising in many related areas, such as solar energy conversion, water splitting, and energy storage. [ABSTRACT FROM AUTHOR]

Cadmium hydroxide nanowalls were directly grown on glass substrate by a hydrothermal method. The concentration of hexamethylenetetramine plays a crucial role for controlling the thicknesses of cadmium hydroxide nanowalls. A part of the cadmium hydroxide nanowalls can be converted to cadmium oxide nanoporous walls by annealing cadmium hydroxide in air at 350 °C for 1 h. Cadmium hydroxide and oxide nanoporous walls exhibited very strong and broad emission properties in the cathodoluminescence spectrum. Furthermore, cadmium hydroxide and oxide nanoporous walls can also provide a higher surface-to-volume ratio to result their higher photocatalytic performance in degradation of methylene blue. [ABSTRACT FROM AUTHOR]

Aligned ZnO nanowire arrays have been grown on the silicon substrates with ZnO seed layer by an aqueous chemical growth process at low reaction temperature. The volumes of ammonium hydroxide solution are not only controlled by the dimension and density of ZnO nanowires, but are also influenced by their optical emission property. The ZnO nanowire arrays exhibit very strong and broad green emission from defect in the cathodoluminescence spectrum. In addition, the ZnO nanowires grown on the silicon substrates can serve as effective and convenient recyclable photocatalysts. Only a very slight decrease in the photodecomposition rate was observed after ten cycles of the photocatalysis experiment. [ABSTRACT FROM AUTHOR]

In this study, we fabricated Er-doped ZnO/CuS/Au core-shell nanowires using two-step wet chemical methods and an ion-sputtering method on a glass substrate as a bifunctional photocatalytic and surface-enhanced Raman scattering (SERS) substrate. The characteristic properties of as-prepared photocatalysts were confirmed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, DR/UV-Vis spectroscopy, and photoluminescence spectroscopy. Compared with Er-doped ZnO nanowires and Er-doped ZnO/CuS core-shell nanowires, Er-doped ZnO/CuS/Au core-shell nanowires exhibited remarkably photocatalytic activity to degrade acid orange 7 solutions under blue LED light. These results ascribed to the Er-doped ZnO/CuS/Au core-shell nanowires can enhance the visible-light absorbance and the separation efficiency of photogenerated electron-hole pairs, inducing their higher photocatalytic activity under blue LED light. In addition, Er-doped ZnO/CuS/Au core-shell nanowires exhibit high sensitivity, a low detection limit (10−6 M), uniformity, recyclability, and stability of SERS performance for detected acid orange 7. [ABSTRACT FROM AUTHOR]

The MoS 2 /ZnO heterostructures can be successfully prepared by combined facile hydrothermal and wet chemistry methods. The surface morphologies, microstructures, crystal structures, chemical compositions, optical properties of the MoS 2 /ZnO heterostructures study through the different kinds of characterization techniques. Compared with MoS 2 nanoflakes, MoS 2 /ZnO heterostructures can increase electron-hole pairs separation, light-harvesting ability, and high specific surface area to improve the photocatalytic decomposition of methylene blue solution under visible light irradiation. Also, MoS 2 /ZnO heterostructures exhibited better visible-light photocatalytic hydrogen evolution activity. Furthermore, the MoS 2 /ZnO heterostructures also exhibited superior photocatalytic reusability and stability for long-term photocatalytic processes. [Display omitted] • MoS 2 /ZnO heterostructures have been synthesized by hydrothermal and wet chemical methods. • MoS 2 /ZnO heterostructures exhibited favorable photocatalytic degradation of MB solution. • MoS 2 /ZnO heterostructures presented a much better performance in H 2 evolution than MoS 2 nanosheets. • MoS 2 /ZnO heterostructures revealed excellent photocatalytic reusability and stability. [ABSTRACT FROM AUTHOR]

• H 2 Ti 3 O 7 nanowires have directly synthesized on the Ti foil by simple hydrothermal and ion‐exchange processes. • H 2 Ti 3 O 7 nanowires revealed very prominent blue emission from surface oxygen vacancies. • H 2 Ti 3 O 7 nanowires exhibited high efficient and reusable photocatalysts under visible-light irradiation. • Holes and hydroxyl radicals played central roles in rhodamine 6G photodegradation. • H 2 Ti 3 O 7 @Ag heterostructures can provide an excellent SERS-active substrate. In the present work, we reported one kind of photocatalytic and surface-enhanced Raman scattering substrate, H 2 Ti 3 O 7 nanowires, which prepared on the Ti foil by the hydrothermal and ion‐exchange methods. The morphologies, crystal structures, chemical compositions, optical properties of the as-prepared substrates investigated via the different kinds of characterization techniques. H 2 Ti 3 O 7 nanowires revealed remarkably enhanced visible-light photocatalytic activity for the degradation of rhodamine 6 G solution compared to Na 2 Ti 3 O 7 nanowires, TiO 2 nanowires, and commercial photocatalysts (TiO 2 and ZnO nanoparticles). These results attributed to the H 2 Ti 3 O 7 nanowires with a higher concentration of oxygen vacancies can enhance the visible-light absorbance, resulting in the higher photocatalytic activity under the visible-light irradiation. The radical-trapping test shows that holes and hydroxyl radicals played central roles in rhodamine 6 G photodegradation. The deposition of Ag nanoparticles on the H 2 Ti 3 O 7 nanowires can also use as a highly sensitive surface-enhanced Raman scattering substrate for detecting rhodamine 6 G solution with a concentration as low as 10−9 M by the ion-sputtering system. [ABSTRACT FROM AUTHOR]

ZnO nanostructures were grown on the stainless steel mesh substrates using an aqueous chemical growth method. The different additives (such as 1,3-diaminopropane and polyethyleneimine) can be used to control the morphology of ZnO nanostructures. ZnO nanowires exhibit very prominent green emission and week UV emission from defect and band gap in the cathodoluminescence spectrum, respectively. The different morphology of ZnO nanostructures on the stainless steel mesh substrates can be used to irradiate UV light for the photocatalytic degradation of four kinds of organic pollutants, such as methylene blue, rhodamine 6G, methyl orange, and 4-nitrophenol. The ZnO nanowires can provide a higher surface-to-volume ratio and stronger defect emission, resulting in their highest photocatalytic performance in 10 W UV light irradiation. The ZnO nanowire arrays on the stainless steel mesh substrates provide a large-scale, facile, low-cost, high surface area, and high photocatalytic efficiency, which shall be of significant value for practical applications of the decomposition of environment pollutants and reusing of wastewater treatment. [ABSTRACT FROM AUTHOR]