One-pot solvothermal synthesis of carbon dots/Ag nanoparticles/TiO2 nanocomposites with enhanced photocatalytic performance

In this paper, we reported a “green” and facile method for one-pot solvothermal synthesis of carbon dots (CDs)/Ag nanoparticles (AgNPs)/titanium dioxide (TiO₂, commercial Degussa P25) ternary nanocomposites with enhanced photocatalytic performance. The characterizations of this ternary photocatalyst were studied at length and our results revealed that the crystalline phase of TiO₂ component remained unchanged after the reaction. While the newborn AgNPs and CDs were tightly attached onto the surface of TiO₂ nanoparticles. The photocatalytic activities of photocatalysts were tested by measurements of photo-degradation on methylene blue (MB) under ultraviolet (UV) and visible light. It was showed that the photocatalytic performance of the ternary photocatalyst was superior to that of single TiO₂ or CDs/TiO₂ binary photocatalyst. It was probably attributed to the synergistic effect of the photoelectrical properties of CDs and the surface plasmon resonance (SPR) effect of AgNPs, which could both enhance the absorption of visible light and hinder the recombination of photogenerated electron-hole pairs.     

Fabrication, characterization and photocatalytic activity of Gd-doped titania nanoparticles with mesostructure

Gd³⁺-doped mesoporous TiO₂ (m-TiO₂) nanoparticles were synthesized via hydrothermal process by using cetyltrimethylammonium bromide (CTAB) as surfactant-directing agent and pore-forming agent. The resulting products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), diffuse reflection spectra (DRS), and linear sweep voltammetry (LSV) etc. Experimental results indicate that different Gd³⁺-doping levels make great impact on the photocatalytic activity of the obtained m-TiO₂ nanoparticles and the 3.5 at.% Gd³⁺-doped m-TiO₂ nanoparticles calcined at 300 °C exhibit the optimal photoactivity on the degradation of Rhodamine B (RB), which is as nearly two times as that of the commercial photocatalyst P25. The mesoporosity, anatase wall as well as the cooperativity of ‘lattice Gd³⁺’ and ‘free Gd³⁺’ in the m-TiO₂ nanoparticles can be used to explain the observed high photoactivity of the doped m-TiO₂ nanoparticles.     

Laser-Induced Silver Nanoparticles on Titanium Oxide for Photocatalytic Degradation of Methylene Blue

Silver nanoparticles doped on titanium oxide (TiO₂) were produced by laser-liquid interaction of silver nitrate (AgNO₃) in isopropanol. Characteristics of Ag/TiO₂ (Ag doped TiO₂) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO₂ photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO₂ was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO₂ photocatalyst under 2 h illumination with a halogen lamp.     

Facile synthesis of a novel photocatalyst with integrated features for industrial effluents treatment

Faster charge transport, excellent charge separation, narrow bandgap energy, lower electron-hole pair recombination rate, and high visible light absorption are the key features of an ideal photocatalyst material. Undoubtedly, semiconductor-based photocatalysts having remarkable charge separation efficiency have attracted considerable attention for degrading hazardous organic pollutants from contaminated water. So herein, a novel composite of reduced graphene oxide (rGO) supported by gadolinium doped bismuth yttrium oxide (Gd-BiYO₃/rGO) was prepared by simple precipitation and ultrasonication method. The photocatalytic efficiency of the Gd-BiYO₃/rGO composite was examined comparatively with pure BiYO₃ and Gd-BiYO₃ samples to degrade Methylene Blue (MB) dye under visible light irradiation. The Gd doping and rGO incorporation into BiYO₃ increased the conductivity, improved the charge transfer efficiency, and impeded the charge recombination, resulting in superior photocatalytic activity of Gd-BiYO₃/rGO. The kinetic studies exhibited the 96.2%, 61.5%, and 48.3% degradation of MB after 80 min irradiation of 1 SUN visible light under Gd-BiYO₃/rGO, Gd-BiYO₃, and BiYO₃, respectively. The Gd-BiYO₃/rGO composite degraded the MB dye at a rate (k = 0.0328 min^-1) that is 5.05 and 2.68-fold higher than pure BiYO₃ and Gd-BiYO₃, correspondingly. The transient photocurrent response of Gd-BiYO₃/rGO was comparatively 4.7 and 2.8 times greater than that of BiYO₃ and Gd-BiYO₃ photocatalysts, respectively. The dominant photocatalytic performance of Gd-BiYO₃/rGO is primarily ascribed to the formation of heterojunctions between rGO nanosheets and Gd-BiYO_3, which facilitate higher visible light absorbance, effective charge separation, and transfer through interfacial layers, more dye adsorption, lower charge transfer resistance, and hamper electron-hole pair recombination. Overall, the electrochemical results suggest that the current study provides an effective way to synthesize a heterostructure photocatalyst for removing organic pollutants from industrial effluents.     

Mn1-xCuxO2/ reduced graphene oxide nanocomposites: Synthesis,characterization, and evaluation of visible light mediated catalytic studies

The narrow optical band gap, higher electrical conductivity, and wider-absorption range are three key features that a good photocatalyst must possess. Herein, we have fabricated Cu-doped MnO₂ (Mn_1-xCu_xO₂) nanostructure by facile wet chemical approach and formed its nanocomposite with r-GO (Mn_1-xCu_xO₂/r-GO) via ultra-sonication approach. The successful replacement of host metal ions (Mn⁴⁺) with the dopant metal ions (Cu²⁺) was supported with the PXRD, FT-IR, and EDX characterizations. The effect of Cu-doping on the band gap and r-GO matrix on the conductivity of the fabricated nanocomposite was also evaluated via Tauc plots and I–V tests, respectively. The photocatalytic efficiency of the fabricated photocatalysts was tested and compared against the methylene blue (MB) under visible light irradiation. The photocatalytic experiments revealed that Mn_1-xCu_xO₂/r-GO photocatalyst exhibited superior photocatalytic aptitude than that of pristine MnO₂ and Mn_1-xCu_xO₂ photocatalysts. More precisely, the Mn_1-xCu_xO₂ photocatalysts degraded 86.89% MB dye at the rate of 0.021 min^?1 after a 90-min exposure to the visible light. Observed superior catalytic activity of the nanocomposite can be attributed to the synergistic effects between the Cu doped MnO₂ and r-GO nanosheets that resulted in its narrow band-gap (2.19 eV) and excellent conductivity (2.217 × 10^?2 Scm^?1).     

Ag nanoparticles loaded TiO2/MWCNT ternary nanocomposite: A visible-light-driven photocatalyst with enhanced photocatalytic performance and stability

A visible light active photocatalyst, Ag/TiO₂/MWCNT was synthesized by loading of Ag nanoparticles onto TiO₂/MWCNT nanocomposite. The photocatalytic activity of Ag/TiO₂/MWCNT ternary nanocomposite was evaluated for the degradation of methylene blue dye under UV and visible light irradiation. Ag/TiO₂/MWCNT ternary nanocomposite exhibits (~9 times) higher photocatalytic activity than TiO₂/MWCNT and (~2 times) higher than Ag/TiO₂ binary nanocomposites under visible light irradiation. The enhancement in the photocatalytic activity is attributed to the synergistic effect between Ag nanoparticles and MWCNT, which enhance the charge separation efficiency by Schottky barrier formation at Ag/TiO₂ interface and role of MWCNT as an electron reservoir. Effect of different scavengers on the degradation of methylene blue dye in the presence of catalyst has been investigated to find the role of photogenerated electrons and holes. Simultaneously, the Ag/TiO₂/MWCNT shows excellent photocatalytic stability. This work highlights the importance of Ag/TiO₂/MWCNT ternary nanocomposite as highly efficient and stable visible-light-driven photocatalyst for the degradation of organic dyes.     

Magnetically recyclable Ni1-xCdxCeyFe2-yO4-rGO nanocomposite photocatalyst for visible light driven photocatalysis

In this study, a magnetically recyclable Ni_1-xCd_xCe_yFe_2-yO₄-rGO (x, y = 0.05) (NCCF-rGO) nanocomposite photocatalyst has been prepared by following a facile in-situ co-precipitation method combined with ultra-sonication means. The as-synthesized magnetically separable NCCF-rGO nanocomposite photocatalyst efficiently degrades methylene blue (MB) dye in comparison to bare Ni_1-xCd_xCe_yFe_2-yO₄ (x, y = 0.05) (NCCF) nanoparticles (NPs) under visible light irradiation. The photo-degradation rate of MB with NCCF-rGO was ~9 times higher than NCCF nanoparticles (NPs). This enhanced photocatalytic performance of NCCF-rGO photocatalyst was due to the presence of reduced graphene oxide, which greatly help in production of photoactive species by reducing the rate of electro-hole pair recombination. The role of photoactive species that were responsible for the photocatalytic degradation of methylene blue has also been investigated. The as-synthesized NCCF-rGO photocatalyst expressed superb chemical stability and photocatalytic activity even after seven cycle runs. Moreover, the NCCF-rGO nanocomposite worked at all pH values and showed good acid resistance. In particular, the as-synthesized NCCF-rGO photocatalyst could be collected for the next cycle run by simply applying an external magnetic field. Hence, the NCCF-rGO nanocomposite could have potential use in organic dyes contained wastewater treatment.     

A unique Cu2O/TiO2 nanocomposite with enhanced photocatalytic performance under visible light irradiation

A unique Cu₂O/TiO₂ nanocomposite with high photocatalytic activity was synthesized via a two-step chemical solution method and used for the photocatalytic degradation of organic dye. The structure, morphology, composition, optical and photocatalytic properties of the as-prepared samples were investigated in detail. The results suggested that the Cu₂O/TiO₂ nanocomposite is composed of hierarchical TiO₂ hollow microstructure coated by a great many Cu₂O nanoparticles. The photocatalytic performance of Cu₂O/TiO₂ nanocomposite was evaluated by the photodegradation of methylene blue (MB) under visible light, and compared with those of the pure TiO₂ and Cu₂O photocatalysts synthesized by the identical synthetic route. Within 120 min of reaction time, nearly 100% decolorization efficiency of MB was achieved by Cu₂O/TiO₂ photocatalyst, which is much higher than that of pure TiO₂ (26%) or Cu₂O (32%). The outstanding photocatalytic efficiency was mainly ascribed to the unique architecture, the extended photoresponse range and efficient separation of the electron-hole pairs in the Cu₂O/TiO₂ heterojunction. In addition, the Cu₂O/TiO₂ nanocomposite also retains good cycling stability in the photodegradation of MB.     

Development of niobium doped tin oxide nanostructure via hydrothermal route for photocatalytic degradation of methylene blue and antimicrobial study

In this work, we discuss the effect of niobium (Nb) doping concentrations of 2% and 4% on the physicochemical characteristics and photocatalytic properties of tin dioxide nanostructure, which were successfully developed by a basic hydrothermal route. Nb-doped SnO₂ were characterized with regards to their optical, structural and photocatalytic features. X-ray diffraction (XRD) analyses display that both pristine and doped tin dioxide had a fine crystalline structure having tetragonal structure. Scanning electron microscopy (SEM) analysis shows that materials exhibited the irregular shaped nanoparticles morphology. Optical absorption analysis using UV–visible spectroscopy revealed a redshift in the bandgap energy for Nb³⁺ doped SnO₂ nanoparticles. Methylene blue aqueous (MB) dye was degraded by 93.78% in 120 min when exposed to 4% Nb doped SnO₂ NPs under visible light. The 4% Nb doped SnO₂ shows elevated photocatalytic activity owing to their greater surface area containing greater active zones responsible for adsorption of larger dye species and good structural stability. Similarly, the 4% Nb doped SnO₂ photocatalysts maintained their excellent stability and photodegradation efficiency over 89% even after being subjected to 5th cycles. The scavenger analysis demonstrates that the superoxide (O₂) radical, a major active substance, performed a crucial role in the mineralization of the aqueous MB dye. The 4% Nb doped SnO₂ also shows remarkable antimicrobial activity. Our finding suggests that doping strategy considered as efficient method that can help to increase the photocatalytic and antimicrobial activity.     

Ternary Pt@TiO2/rGO Nanocomposite to Boost Photocatalytic Activity for Environmental and Energy Use

This work explores the effect of ternary nanostructure for the enhanced photocatalytic degradation of pollutants and dyes. One-pot solvothermal-assisted approach was used for producing nanosized Pt@TiO₂ hybrid nanoparticles (NPs) decorated on reduced graphene oxide (rGO) layers. The microstructure, morphology, chemical composition, and optical absorption of the designed photocatalyst was successfully characterized (using XRD, TEM, Raman, UV–visible absorption spectra, and XPS techniques). The ternary Pt@TiO₂-rGO photocatalyst consist of monodisperse quasi-spherical Pt@TiO₂ NPs with an average size of 11 nm deposited on the rGO nanosheets. Furthermore, Pt@TiO₂-rGO was further investigated for the photodegradation of pesticide and dyes under UV and visible light. The ternary Pt@TiO₂-rGO photocatalyst proved a significant improvement on the photodecomposition of pollutants compared to hybrid Pt@TiO₂. The Pt@TiO₂-rGO photocatalyst was found to show seven- and threefold increase in the photocatalytic activity compared to TiO₂ and Pt@TiO₂ NPs, respectively which resulted from the high surface area of rGO and as well as the strong Pt/TiO₂/rGO interactions which ensured excellent properties of charge separation. On the other hand, the ternary photocatalyst exhibited very good recycle and reuse capacity up to five cycles.

     

A g-C3N4 supported graphene oxide/Ag3PO4 composite with remarkably enhanced photocatalytic activity under visible light

In this work, a ternary composite photocatalyst of graphitic carbon nitride (g-C₃N₄), graphene oxide (GO), and Ag₃PO₄ was prepared through a simple precipitation route, in which Ag₃PO₄ nanoparticles covered or wrapped with GO sheets are supported on g-C₃N₄ sheets. The composite photocatalyst displays enhanced absorption in the visible region, and exhibited superior photocatalytic activity compared with single-component or binary composite photocatalysts in the photocatalytic decomposition of Rhodamine B. The enhancement of photocatalytic activity could be attributed to the synergistic effect among them. The ternary composite also exhibited enhanced stability, but further efforts should be made to make it more stable.     

Experimental analysis and optimization of the synthesizing property of nitrogen‐modified TiO2 visible‐light photocatalysts

BACKGROUND: The aim of this study was to investigate improvement of the photocatalytic activity of visible‐light driven nitrogen‐modified TiO₂ (N‐TiO₂) powder toward methyl blue (MB) and direct blue‐86 (DB‐86) dyes. The Taguchi method with an L₉ orthogonal array was applied to plan the synthesis parameters, i.e. nitrogen sources, nitrogen source concentrations, stirring time and calcined temperatures. 95% confirmation experiments were undertaken to verify the effectiveness of the Taguchi method. RESULTS: All N‐TiO₂ photocatalysts were shifted toward the visible light region with the optical band gap (Eg). Nitrogen source concentrations were significant parameters for the photocatalytic decolorization rate constants (k values). In comparison with pure TiO₂, the photodecolorization behavior of N‐TiO₂ toward DB‐86 was superior with a reaction rate constant of 1.68 × 10^?3 min^?1, and a 4 h photodecolorization efficiency of 34%. CONCLUSION: The Taguchi method was reported to alter the surface properties of commercial Degussa P25 TiO₂, which could then be used as a visible‐light driven photocatalyst. The visible‐light‐driven photocatalyst was investigated to determine material characteristics. Greater photodecolorization of MB and DB‐86 dye pollutants using optimally‐prepared N‐TiO₂ under visible light irradiation was successfully obtained. Copyright © 2011 Society of Chemical Industry     

Novel g-C3N4 nanosheets/CDs/BiOCl photocatalysts with exceptional activity under visible light

We fabricated novel ternary nanocomposites through integration of C-dots (carbon dots), BiOCl, and nanosheets of graphitic carbon nitride (g-C₃N₄ nanosheets) by a cost-effective route. The fabricated photocatalysts were subsequently characterized by XRD, EDX, TEM, HRTEM, XPS, FT-IR, UV-vis DRS, TGA, BET, and PL methods to gain their structure, purity, morphology, optical, textural, and thermal properties. In addition, the degradation intermediates were identified by gas chromatography-mass spectroscopy (GC-MS). Photocatalytic performance of the synthesized samples was studied by photodegradations of three cationic (RhB, MB, and fuchsine), one anionic (MO) dyes, one colorless (phenol) pollutant and removal of an inorganic pollutant (Cr(VI)) under visible light. It was revealed that the ternary nanocomposite with loading 20% of BiOCl illustrated superlative performances in the selected photocatalytic reactions compared with the corresponding bare and binary photocatalysts. Visible-light photocatalytic activity of the g-C₃N₄ nanosheets/CDs/BiOCl (20%) nanocomposite was 42.6, 27.8, 24.8, 20.2, and 15.9 times higher than the pure g-C₃N₄ for removal of RhB, MB, MO, fuchsine, and phenol, respectively. Likewise, the ternary photocatalyst showed enhanced activity of 15.3 times relative to the g-C₃N₄ in photoreduction of Cr(VI). Moreover, the ternary nanocomposite exhibited excellent chemical stability and recyclability after five cycles. Finally, the mechanism for improved photocatalytic performance was discussed based on the band potential positions.     

Hydrothermal synthesis of CdS/CoWO4 heterojunctions with enhanced visible light properties toward organic pollutants degradation

Effective solar energy harvesting and charge carrier separation are two key factors of the photocatalysis system. In this work, the heterojunction photocatalyst of CdS/CoWO₄ was fabricated by a facile hydrothermal method. Compared with the pristine CdS and CoWO₄, the CdS/CoWO₄ heterojunction photocatalyst showed enhanced photocatalytic activity for the methylene blue (MB) degradation under visible light irradiation. Particularly, the sample with molar ratio of CdS:CoWO₄ (sample C2) controlled at 3:5 showed the highest MB degradation ratio (83%) in 1 h among all samples, which is about 3 times over the pure CdS and 8 times over pure CoWO₄, respectively. The greatly enhanced photocatalytic activity (3–8 times) of CdS/CoWO₄ is due to the efficient separation of electron-hole pairs by the heterojunction structure and strong visible light absorption of CdS. This work provides a new insight into the application of tungstate-based heterojunction photocatalysts in environmental remediation.     

Enhanced visible‐light‐driven photocatalytic activities of LiInO2 by Mo6+‐doping strategy

A novel visible‐light‐driven photocatalyst of Mo‐doped LiInO₂ nanocomposite was successfully synthesized through a sol‐gel method. The effect of Mo‐doping concentrations on the microstructures and properties of LiInO₂ was characterized by X‐ray diffraction, scanning electron microscope, X‐ray photoelectron spectroscopy, photoluminescence, and ultraviolet‐visible absorption spectra. The photocatalytic properties of the as‐prepared samples were evaluated by the photocatalytic degradation of methylene blue (MB) dye under visible‐light irradiation. The results demonstrated that the photocatalytic activity of 6% Mo‐LiInO₂ reached to 98.6%, which was much higher than that of the undoped photocatalyst LiInO₂ (only 46.8%). The enhanced photocatalytic activity is ascribed to Mo‐doping strategy. The holes play an important role in the process of the photodegradation of MB. The superior photocatalytic activity of the as‐prepared Mo‐LiInO₂ nanocomposites suggests a potential application for organic dye degradation of wastewater remediation. This work provides a further understanding on tailoring the band structure of semiconductor photocatalyst for enhancing visible‐light absorption and promoting electron‐hole separation by Mo‐doping strategy.     

Transparent zinc silicate/ zinc oxide crystallized glass-ceramics for water remediation application under visible light

The present study focuses on taking advantage of both Zinc Silicate (Zn₂SiO₄) and Zinc Oxide (ZnO) crystals in the glass matrix for enhancing photocatalytic activity. The fabricated samples were used as a photocatalyst for degrading ～ 5 mg/L concentrated “Methylene Blue” (MB) and “Rhodamine B” (RB) dye separately under visible light. For this, 44 SiO₂:11 Al₂O₃:35 ZnO:10 K₂O compositions were prepared via the traditional melt quench process followed by heat treating at a temperature of 750 °C at 2, 4, and 6 h. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) was employed to characterize the fabricated samples. The bandgap measured from Differential reflectance spectroscopy (DRS) was found to decrease with an increase in the heat treatment duration. 44 SiO₂:11 Al₂O₃:35 ZnO:10 K₂O composition heat-treated at 750 °C for 2 h degraded ～59% and ～71% of Rhodamine B (RB) dye and Methylene Blue (MB) dye under visible light in 4 h.     

Hydrothermal preparation of Sn3O4/TiO2 nanotube arrays as effective photocatalysts for boosting photocatalytic dye degradation and hydrogen production

The efficient TiO₂ NTs/Sn₃O₄ photocatalysts were synthesized by the hydrothermal deposition of Sn₃O₄ on TiO₂ nanotube arrays (TiO₂ NTs), and the morphology, microstructure and photocatalytic property were adjusted by changing the alkali kind. The TiO₂ NTs/Sn₃O₄ prepared with NaOH exhibited the outstanding photoelectric conversion and photocatalytic environment remediation/H₂ evolution. The methylene blue (MB) dye and Cr(VI) could be removed by the as-prepared photocatalysts under visible light irradiation, and ?O₂^?/?OH radicals were the main active species for MB photodegradation. Furthermore, the high photocatalytic H₂ evolution rate was as high as 6.49 μmol cm^?2 h^?1. The outstanding photocatalytic activity and stability of TiO₂ NTs/Sn₃O₄ photocatalysts would exhibit attractive prospect in the wastewater remediation and electric energy/hydrogen generation.     

Surfactant-free synthesis of a novel octahedral ZnFe2O4/graphene composite with high adsorption and good photocatalytic activity for efficient treatment of dye wastewater

Recently, significant effort has been made toward the development of graphene-based visible-ligh-responsive photocatalysts and their application to dye wastewater treatment. Herein, a series of octahedral ZnFe₂O₄/graphene (ZnFe₂O₄-G) nanocomposites were synthesized using a one-pot solvothermal reaction without the need of a surfactant as novel bifunctional materials exhibiting both high adsorption and good visible-light-responsive photocatalyst properties. The crystal structure, morphology and photocatalytic degradation properties, as well as adsorption behavior, of the octahedral ZnFe₂O₄/graphene composites were investigated in detail. The adsorption capacity and UV–vis spectrometry results indicate that the dye removal efficiency over the samples followed the order of: methylene blue (MB) > rhodamine B (RhB) > methyl orange (MO). The ZnFe₂O₄-G materials exhited enhanced photocatalytic degradation properties for cationic dyes (MB and RhB) compared to those for the anionic dye (MO). In addition, the experimental results indicate that the ZnFe₂O₄-G materials can decompose H₂O₂ in the visible-light photocatalytic process to form hydroxyl radicals (•OH), which are mainly responsible for the photodegradation of the organic contaminants.     

Synergistic effect of binary metal doping and nanotechnology to boost the light-harvesting properties of rare earth metal oxide

Material scientists are currently focusing on employing photocatalytic materials to detoxify household and industrial waste to tackle rising water pollution problems. Narrow-bandgap materials are more valuable than other photocatalysts due to their visible light-harvesting characteristics. In this research, binary metal-doped cerium oxide (3 mol % Cd, 5 mol % Zn–CeO₂ = CZC-1 and 5 mol % Cd, 3 mol % Zn–CeO₂ = CZC-2) photocatalysts were successfully prepared through the facile and affordable co-precipitation method. The crystal structure, chemical functionality, morphology, composition, and optical behavior of the as-prepared binary metal-doped cerium oxide samples were explored via advanced physiochemical techniques. UV–Vis spectroscopy revealed that the CZC-2 photocatalyst possessed a relatively lower bandgap (2.15 eV) than the counterpart (CZC-1); hence it could be used as a visible-light triggered catalyst. The binary metal-doped photocatalyst's dye and microbe degradation efficacies were compared using methylene blue and P. Vulgaris, respectively. The CZC-2 photocatalyst showed superior dye degradation activity and mineralized almost 97% dye after 60 min irradiation time. Even after five reuse cycles, the recyclability tests showed that the catalytic efficiency of CZC-2 NPs only dropped by 4.5%. The CZC-2 photocatalyst's high photocatalytic activity and long-term stability show that the CZC-2 nanoarchitecture can be used in practical ways to clean up the environment.     

Graphene‐supported nickel ferrite: A magnetically separable photocatalyst with high activity under visible light

A straightforward strategy is designed for the fabrication of a magnetically separable NiFe₂O₄‐graphene photocatalyst with different graphene content. It is very interesting that the combination of NiFe₂O₄ nanoparticles with graphene sheets results in a dramatic conversion of the inert NiFe₂O₄ into a highly active catalyst for the degradation of methylene blue (MB) under visible light irradiation. The significant enhancement in photoactivity under visible light irradiation can be ascribed to the reduction of GO, because the photogenerated electrons of NiFe₂O₄ can transfer easily from the conduction band to the reduced GO, effectively preventing a direct recombination of electrons and holes. The results of the kinetic study indicated that the rate‐determining stage is the adsorption process of MB molecules. NiFe₂O₄ nanoparticles themselves have a strong magnetic property, which can be used for magnetic separation in a suspension system, and, therefore, the introduction of additional magnetic supports is no longer necessary. © 2011 American Institute of Chemical Engineers AIChE J, 2012