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The reduced graphene oxide supported Zn-doped Bi2MoO6 nanocomposites (ZnxBi2-xMoO6/RGO) are synthesized by an easy one-step solvothermal method for the rapid degradation of ciprofloxacin (CIP). Characterization analyses show that Bi2MoO6 nanosheets are uniformly supported on RGO, for which the agglomeration of Bi2MoO6 is effectively inhibited, leading to more exposure of surface active sites. The degradation rate of Zn0.1Bi1.9MoO6/RGO5 on CIP reached 90% after 120 min of visible light irradiation, which was 10.4 times the rate of unsupported Bi2MoO6. Zn doping and RGO loading synergistically reduce the recombination rate of photogenerated electron–hole pairs and result in the enhanced photocatalytic performance. Compared with previously reported catalysts, Zn0.1Bi1.9MoO6/RGO5 can get higher degradation efficiency with shorter time and less dosage. In addition, after five cycles, the degradation efficiency is maintained at about 85%, showing perfect cycling stability of Zn0.1Bi1.9MoO6/RGO5. Photocatalytic mechanism suggests that the photogenerated •O2− and h+ are main species for degrading CIP based on ZnxBi2-xMoO6/RGO complex. [ABSTRACT FROM AUTHOR]

A ternary visible light-driven catalyst, reduced graphene oxide (RGO)-based Bi2MoO6 (BMO), modified with CdS, was synthesized for the degradation of ciprofloxacin through solvothermal method. Neither toxic reductant nor toxic solvent was used. The structural characterization shows that graphene oxide sheets were reduced, while BMO nanoplates and CdS nanoparticles grew to form CdS–BMO/RGO simultaneously. The modification of BMO with CdS and RGO extraordinarily enhances the photocatalytic performance of BMO on the degradation of ciprofloxacin (CIP) under visible light irradiation. The photodegradation rate of CIP over CdS–BMO/RGO photocatalyst is approximately 24 times faster than that of BMO. The improvement of the photocatalytic performance is attributed to the synergistic effect among CdS, BMO and graphene. Moreover, CdS–BMO/RGO exhibits better performance on the degradation of CIP than most bismuth oxide-containing catalysts recently reported. Degradation of various organic contaminants in addition to CIP has also been studied, showing that CdS–BMO/RGO exhibits much higher photocatalytic performance on degrading molecules containing smaller conjugated system. [ABSTRACT FROM AUTHOR]

Here, we report a simple approach to fabricate 3D hierarchical peony-like Ag/BiWO hybrid photocatalyst through one-step hydrothermal method with l-leucine as a template. The morphology and structure of the resultant materials were characterized by various analytical methods, such as X-ray diffraction, field emission scanning electron microscopy and UV-Vis diffuse reflectance spectra. The photocatalytic performance of BiWO and Ag/BiWO samples was evaluated by degrading organic dye and antibiotic in water under visible light irradiation. A series of results indicated that loaded Ag nanoparticles significantly improve the photocatalytic activity of BiWO. In addition, the possible mechanism was proposed that the enhanced photocatalytic activity was resulted from the unique configuration of peony-like morphology that favorable for the adsorption of organic compounds and the high Schottky barriers between interface of Ag NPs and BiWO, which promoted the transfer of photogenerated electrons from BiWO to Ag NPs. Meanwhile, noble metal Ag can induce surface plasmon resonance leading to the better visible light absorption of BiWO. [ABSTRACT FROM AUTHOR]

A magnetically separable FeO@BiO-RGO core-shell heterostructured photocatalyst was successfully prepared through a self-assembly method for the first time. The FeO nanoparticles with an average diameter of 200 nm was wrapped by approximately 50 nm thick layer of BiO to form unique FeO@BiO nanospheres, then loaded on the surface of reduced graphene oxide (RGO). Compared with pure BiO and FeO@BiO, the as-synthesized FeO@BiO-RGO nanocomposites showed broadened visible light adsorption range, increased charge separation efficiency, excellent photocatalytic activity and cyclic stability for degradation of quinolone antibiotics (QAs) under visible light irradation. The degradation rate of ciprofloxacin (CIP) with FeO@BiO-RGO photocatalyst could reach 98.3% in 240 min and it was still above 80% after ten photocatalytic reaction cycles. More importantly, benefiting from the introduction of FeO and RGO, the FeO@BiO-RGO nanocomposites could effectively prevent the rapid recombination of photogenerated electron-hole pairs and photocorrosion phenomenon of BiO, which made it become a highly stable and durable photocatalyst. These attractive features make the FeO@BiO-RGO nanocomposites to be a promising photocatalyst for visible light photocatalytic degradation of QAs in water pollutants treatment. [ABSTRACT FROM AUTHOR]

Abstract: We designed the reduced graphene oxide (RGO)-based Ag@Ag3PO4 hetero-photocatalyst by coprecipitation and photoreduction. The graphene sheets are fully coated with Ag@Ag3PO4 nanocrystals with an average diameter of 200nm. Ag@Ag3PO4/RGO hetero-photocatalyst showed strong absorbance in the visible region and low recombination rate of holes and electrons. Compared with Ag@Ag3PO4, Ag3PO4 and Ag3PO4/GO, Ag@Ag3PO4/RGO hetero-photocatalyst exhibited greatly enhanced photocatalytic activity under visible-light irradiation for the photodegradation of not only cationic dye (rhodamine B) but also anionic dye (methyl orange), which is usually difficult to be degraded over other catalysts. Moreover, the hetero-photocatalyst can be used repetitively with a high photocatalytic activity. The mechanism was explored and confirmed, showing that the improvements are attributed to the effective charge transfer from Ag3PO4 nanocrystals to RGO through Ag nanoparticles, which hinders the recombination of electron/hole pairs and the photocorrosion of Ag3PO4. This study could provide new insights in the design and fabrication of highly efficient visible-light-driven novel photocatalysts for solving energy and environmental problems. [Copyright &y& Elsevier]

The Ce-doped NiAl layered double hydroxide/reduced graphene oxide (NiAlCe LDH/RGO) composite was synthesized by a facile one-step hydrothermal method. The structure and morphology of the composite were investigated. NiAlCe LDH/RGO has large specific surface area and uniform dispersion. The presence of Ce and RGO accelerate separation of photo-generated charges, leading to an outstanding photocatalytic performance for the degradation of ciprofloxacin (CIP). As a result, the NiAlCe LDH/RGO exhibits a high photocatalytic degradation efficiency of 94% under visible light irradiation, which is much higher than that of pristine NiAl LDH (36%). Moreover, the NiAlCe LDH/RGO possesses excellent cycling stability of 84% efficiency retention after five consecutive tests. In addition, the reaction mechanism of photocatalyst was investigated by ESR and radical scavenger experiments. [Display omitted] • NiAlCe LDH/RGO composite was fabricated via one-step hydrothermal method. • NiAlCe LDH/RGO shows desirable photocatalytic performance on the degradation of CIP. • NiAlCe LDH/RGO presents good recycling stability. [ABSTRACT FROM AUTHOR]

A magnetic heterogeneous α‐Fe2O3/CdS‐RGO (RGO: reduced graphene oxide) composite photocatalyst was synthesized using the one‐step hydrothermal method. The α‐Fe2O3 and CdS nanoparticles with a diameter range of 20~60 nm were synchronously loaded/distributed on the surface of RGO. The as‐synthesized α‐Fe2O3/CdS‐RGO nanocomposites were analyzed using X‐ray diffraction, Fourier transform‐infrared spectra, BET surface area, scanning electron microscopy, transmission electron microscopy, UV–Vis diffusive reflectance spectra and Raman spectroscopy. Compared with the pure CdS, α‐Fe2O3 and α‐Fe2O3/CdS nanoparticles, the α‐Fe2O3/CdS‐RGO nanocomposites expanded the adsorption range of visible‐light, and showed significant photocatalytic performance and cyclic stability for degradation of methylene blue in visible light. Also, the remarkable catalytic performances mainly depend on its special structure of the α‐Fe2O3/CdS‐RGO, which enabled the effective separation of the electron–hole pairs. These attractive features make the α‐Fe2O3/CdS‐RGO nanocomposite to be a photocatalyst with great application potential in water pollutants treatment. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (RGO) supported CdS@CuS core-shell nanorods (CdS@CuS/RGO) were prepared by a simple, solvothermal method involving cation-exchange for efficient degradation of the fluoroquinolone antibiotic, ciprofloxacin (CIP). CdS@CuS/RGO delivers superior photocatalytic degradation of CIP in simulated sunlight. Ascribed to the unique nanostructure, the CIP degradation efficiency of CdS@CuS/RGO reaches 91.5%, which is higher than that of CdS (67.1%) alone. Compared with previously reported catalysts, CdS@CuS/RGO exhibits higher degradation efficiency in less time and lower dosage. Furthermore, its degradation efficiency remains at around 81.5% after five usage cycles, which represents excellent cycling stability. Free radical scavenging experiments show that superoxide radicals and holes play important roles in the degradation. The CdS@CuS/RGO utilizes the synergistic effects of CdS, CuS and RGO to effectively retard the photo corrosion of CdS upon visible light exposure, reduce the band-gap energy, suppress the recombination of photo-generated electron-hole pairs and promote the adsorption of catalyst toward CIP, thereby, enhancing the catalytic performance of the composite. [Display omitted] • CdS@CuS/RGO nanocomposites with core-shell structure prepared by simple solvothermal method. • CuS nanoparticles deposited onto a CdS surface by in situ ion exchange strategy. • CdS@CuS/RGO show enhanced visible-light photocatalytic degradation of ciprofloxacin. • Possible photocatalytic mechanism of hybridizing CdS and CuS with RGO. [ABSTRACT FROM AUTHOR]

Graphical abstract Mechanism of photocatalytic degradation of RhB in the presence of Bi/BiOBr/G under visible light irradiation. Highlights • Graphene based Bi modified BiOBr photocatalyst was synthesized. • A facile means was used employing ethylene glycol as solvent and reducing reagent. • The photocatalyst shows high photocatalytic activity for the degradation of RhB. • Synergistic effect of Bi, BiOBr and graphene enhances the photocatalytic activity. Abstract A ternary photocatalyst, graphene based bismuth modified bismuth(III) oxybromide (Bi/BiOBr/G), was synthesized via a facile one-step solvothermal method using only ethylene glycol as both solvent and reducing reagent. Bi/BiOBr/G exhibits higher photocatalytic activity than bismuth(III) oxybromide (BiOBr) on degradation of Rhodamine B under visible-light illumination, and the photodegradation rate is 4.9 times that of BiOBr. The enhanced photocatalytic activity is attributed to the synergistic effect among Bismuth, graphene and BiOBr, which can effectively promote the visible-light absorption of Bi/BiOBr/G and the separation of photogenerated charge carriers. The conditions influencing the photocatalytic performance of Bi/BiOBr/G were also investigated in detail, as well as the photocatalytic mechanism of the degradation. [ABSTRACT FROM AUTHOR]

The ZnAl mixed metal-oxides (MMOs)/graphene nanocomposites were successfully fabricated by a facile hydrothermal method combined with a calcination process. The thermal treatment enables simultaneously the formation of ZnO/ZnAl 2 O 4 heterogeneous structure, which are uniformly decorated on the surface of graphene, accompanying with the reduction of graphene oxide. The as-prepared heterostructure photocatalysts were well characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectroscopy (DRS) to conduct investigations into the phase structures, microstructure and optical capability. The ZnAl MMO/RGO 20 composite displayed favorable adsorption property and photo-degradation efficiency for Ciprofloxacin (CIP) aqueous solution under visible light. The photo-degradation efficiency of the as-prepared ZnAl MMO/RGO 20 was 3.0 and even 4.6 times higher than that of ZnAl MMO and pure ZnAl LDH, respectively. The improvement of photocatalytic performance is ascribed to the synergistic effect of heterogeneous structure coupled with graphene, which realizes efficient charge separation efficiency, enlarged visible light adsorption range, and chemical stability of hybrid nanocomposite. The results of EIS, PL and photocurrent response also explained the best performance of ZnAl MMO/RGO 20 nanocomposite. Besides, the mechanism of ZnAl MMO/RGO 20 photocatalytic system was proposed and analyzed in detail. [ABSTRACT FROM AUTHOR]

A 2D/2D Bi 4 O 5 Br 2 /Bi 2 WO 6 Z-scheme heterojunction has been constructed by a simple chemical co-precipitation approach followed by a hydrothermal process, and utilized as an efficient photocatalyst for the degradation of organic pollutants under visible-light. Impressively, the optimized Bi 4 O 5 Br 2 /Bi 2 WO 6 achieved satisfactory degradation efficiency of CIP (91.0%), NOR (89.6%), TCH (87.6%) and RhB (95.6%), demonstrating the versatility of Bi 4 O 5 Br 2 /Bi 2 WO 6 Z-scheme heterojunction for photodegradation of various organic pollutants. [Display omitted] • 2D/2D Bi 4 O 5 Br 2 /Bi 2 WO 6 Z-scheme heterojunction was prepared by a hydrothermal method. • Intimate interfacial interaction reinforces the migration and separation of photoinduced carriers. • The 2D/2D nanostructure and Z-scheme heterojunction jointly enhance the photodegradation activity. • The degradation pathway and photocatalytic mechanism are proposed. Enhancing the heterointerface contact determined by the dimensionality of each component is essential for the rapid migration of photogenerated charge carriers. Herein, the 2D/2D Bi 4 O 5 Br 2 /Bi 2 WO 6 Z-scheme heterojunction was successfully synthesized through a simple chemical co-precipitation followed by a hydrothermal process. Remarkably, the optimized Bi 4 O 5 Br 2 /Bi 2 WO 6 heterojunction achieved superior photocatalytic efficiency of 91.0% and ascendant stability for the degradation of ciprofloxacin (CIP) under visible light illumination. More importantly, degradation pathway and photocatalytic mechanism analysis revealed that the reinforced photodegradation efficiency can be ascribed to the intimate heterointerface between 2D Bi 4 O 5 Br 2 and 2D Bi 2 WO 6 , which facilitated the fast migration and separation of photoinduced carriers, thus enhancing the photocatalytic activity. Furthermore, the effect of pH, CIP concentration, inorganic cations and anions, and different contaminants were systematically investigated to explore the potential of practical applications. This work gives rational insight into the developing 2D/2D Z-scheme heterojunction for environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel Bi 4 O 5 Br 2 /MIL-88B(Fe) composites were fabricated via a two-step method. • BMF showed excellent 93.04% removal efficiency on TCH degradation. • Z-scheme system formed internal electric field and enhanced the oxidation capacity. • EPR tests and scavenger experiments confirmed the main radicals of ·O 2 –. • The photocatalytic degradation mechanism was elucidated. Bi 4 O 5 Br 2 /MIL-88B(Fe) Z-scheme heterojunction photocatalyst is fabricated by a facile hydrothermal followed by a coprecipitation method. The heterojunction catalyst greatly improved the visible light utilization and has shown excellent photodegradation performance for tetracycline hydrochloride (TCH). The high oxidation capability, unique charge migration, and enhanced photogenerated charge carrier separation of Z-scheme Bi 4 O 5 Br 2 /MIL-88B(Fe) heterojunction simultaneously contributed to improved catalytic performance. Meanwhile, Z-scheme Bi 4 O 5 Br 2 /MIL-88B(Fe) heterojunction has achieved the highest photodegradation of TCH with ∼93.04 % within 80 min. In addition, the time-resolved photoluminescence (PL) emission decay spectra confirmed a prolonged lifetime of electron excitation with a fluorescence lifetime of ∼1.08 ns compared with Bi 4 O 5 Br 2 (t = 0.95 ns). Furthermore, following operating conditions, such as pH, solution concentration, various ionic species, etc., the Bi 4 O 5 Br 2 /MIL-88B(Fe) heterojunction has shown excellent photodegradation of TCH in various environmental conditions with high photostability. Additionally, a substantial charge transfer mechanism and TCH photodegradation pathway were explained. This work demonstrates a promising approach to constructing other high-efficiency Z-scheme heterojunction materials for wastewater treatments. [ABSTRACT FROM AUTHOR]

A magnetically separable Fe 3 O 4 @CuO-RGO (RGO: reduced graphene oxide) core-shell heterostructured photocatalysts were synthesized for the first time by low temperature hydrothermal method. This novel method enables simultaneously the decoration of Fe 3 O 4 @CuO spheres on both sides of graphene sheets as well as the reduction of graphene oxide. The hetero-photocatalysts were characterized by X-ray diffraction, Fourier-transform infrared spectra, field-emission scanning electron microscope, transmission electron microscopy, energy dispersive X-ray spectroscopy, UV–vis diffusive reflectance spectra, photo luminescence and X-ray photoelectron spectroscopy. The results demonstrated that the as-prepared Fe 3 O 4 @CuO-RGO composites possessed enlarged visible light adsorption range and enhanced charge separation efficiency compared with that of the pure CuO and Fe 3 O 4 @CuO. Also, the unique structure afforded Fe 3 O 4 @CuO-RGO desirable photocatalytic activity and stability for the degradation of methylene blue under visible-light irradiation. [ABSTRACT FROM AUTHOR]

The residual antibiotics in pharmaceutical wastewater have a great impact on the efficiency and stability of wastewater biological treatment process, and prefer to be treated by advanced oxidation process beforehand. In this study, we synthesized a novel Bi 2 WO 6 /BiOBr/reduced graphene oxide (RGO) photocatalyst by one-step hydrothermal method and applied it to the photocatalytic oxidation of ciprofloxacin. The characterization results showed that the photocatalyst had a heterojunction structure and a broadening light absorption range. RGO in the composite effectively reduced the band gap of Bi 2 WO 6 /BiOBr and promoted the separation of photogenerated charge carriers. Neutral pH condition was favor of the adsorption and degradation of ciprofloxacin by Bi 2 WO 6 /BiOBr/RGO, and the ciprofloxacin removal efficiency could be up to 90.7 % with the optimal molar ratio of Bi 2 WO 6 to BiOBr (1:1) and RGO content (5 wt%). In the free radical quenching experiment, superoxide radicals and photogenerated holes were determined to be major contributors for the photocatalytic degradation of ciprofloxacin. Furthermore, 71.3 % of ciprofloxacin could be removed through mineralization during the photocatalysis process, and the residual pollutants did not significantly affect the biological nitrogen removal process. [Display omitted] • A novel Bi 2 WO 6 /BiOBr/RGO photocatalyst was prepared by one-step method. • Bi 2 WO 6 /BiOBr/RGO excelled in light absorption and electron–hole pairs separation. • Ciprofloxacin could be photocatalytic degraded by Bi 2 WO 6 /BiOBr/RGO efficiently. • The degradation products of ciprofloxacin had no significant biological toxicity. [ABSTRACT FROM AUTHOR]

The Fe-doped BiOCl/reduced graphene oxide (Fe/BiOCl/RGO) photocatalyst was synthesized for ciprofloxacin (CIP) degradation under visible light irradiation via a facile and controllable solvothermal approach. Fe-doping and RGO incorporated greatly inhibit the agglomeration of BiOCl and significantly enhance the photodegradation activity by facilitating the separation of photogenerated electron-hole pairs, which could almost completely degrade CIP solution in 180 min. Moreover, Fe/BiOCl/RGO reaches the highest rate constant of 0.021 min−1, which is 2.1 and 4.4 times larger than those of Fe/BiOCl and BiOCl, respectively. Besides, Fe/BiOCl/RGO exhibits excellent stability, which can remain ∼90% after five cycling degradation. Photogenerated ·OH and h+ for CIP degradation are confirmed as the main active species through free radical capture experiments. The improved photocatalytic activity of Fe/BiOCl/RGO is attributed to the strong synergistic effect of Fe-doping and RGO addition, which efficiently extends the visible light absorption extent, along with accelerating the separation and conversion of photogenerated electrons and holes, thus promoting the utilization of photocatalysts under visible light irradiation. [Display omitted] • Nearly 100% of ciprofloxacin can be photodegraded by Fe/BiOCl/RGO within 180 min. • Fe/BiOCl/RGO exhibits great stability and remain ∼90% after five cycling degradation. • The hole and hydroxyl radicals are the dominant photoactive species. • Modification of BiOCl with Fe and RGO greatly enhances the photocatalytic activity. [ABSTRACT FROM AUTHOR]

• ZCL nanoplate-decorated CdS nanowires are prepared in-situ via a simple method. • CdS/ZCL exhibit significantly enhanced visible light photocatalytic activities. • Tight interface contact between CdS and ZCL promotes the transfer of carriers. • CdS/ZCL have wide applicability in photocatalytic removal of contaminants. CdS/ZnCr layered double hydroxide (CdS/ZCL) was prepared in-situ through a simple hydrothermal method and proved to be an efficient photocatalyst for removing Cr(VI) in wastewater. Structural characterization shows that ZCL nanoplates uniformly grow on the surface of CdS nanowires. Cr(VI) in the simulated wastewater can be completely removed within 30 min under visible-light illumination, using CdS/ZCL as the catalyst. The reduction rate is much faster than many other catalysts reported recently and calculated to be 3.1 and 60.3 times that of CdS and ZCL, respectively. The excellent catalytic performance of CdS/ZCL is ascribed to the synergy between CdS and ZCL. More importantly, CdS/ZCL also performs well in the photocatalytic degradation of some organic contaminants in wastewater. [ABSTRACT FROM AUTHOR]

The Fe 3 O 4 @ZnO-RGO (RGO: reduced graphene oxide) composite with magnetic separation was firstly obtained using the low-temperature hydrothermal method. Fe 3 O 4 nanoparticles with an average size of 200 nm were coated by a ZnO layer about 50 nm thick, forming the unique Fe 3 O 4 @ZnO nanospheres, and then loaded on the RGO surface. The structure, morphology and photocatalytic properties of as-synthesized Fe 3 O 4 @ZnO-RGO were analyzed using the X-ray diffraction (XRD), Fourier-transform infrared spectra (FTIR), Transmission electron microscopy (TEM), UV–vis diffusive reflectance spectra, and Photo-luminescence spectra (PL). Compared with the pure ZnO and Fe 3 O 4 @ZnO nanoparticles, Fe 3 O 4 @ZnO-RGO has a wider adsorption range for methylene blue (MB) in visible light, and good photocatalytic activity and cyclic stability. Also, the unique structural characteristics of Fe 3 O 4 @ZnO-RGO enabled the separation of electron-hole pairs, which lead to its enhanced photocatalytic properties. These attractive properties make Fe 3 O 4 @ZnO-RGO nanocomposite expect to be a photocatalyst with great potential in water pollutants treatment. • A magnetically separable Fe 3 O 4 @ZnO-RGO photocatalyst was firstly synthesized by low-temperature hydrothermal method. • The combination of Fe 3 O 4 and ZnO with RGO leads to a high visible-light catalyst active for degradation of methylene blue. • The reinforce in visible-light catalytic activity can owe to the strong photon-generated carrier separation ability. • The composite catalyst is easily recycled due to its magnetic separability. [ABSTRACT FROM AUTHOR]