Photodegradation Rate Of Methylene Blue Research Articles

SYNTHESIS OF Ag-MODIFIED TiO2 SOL-GEL FILMS AND ITS APPLICATION AS PHOTOCATALYSTS FOR METHYLENE BLUE DEGRADATION

In the study, the photocatalytic activity of TiO2 films that are created by dip-coating from a sol that contained titanium (IV) isopropoxide, monoethanolamine, and 2-methoxyethanol is demonstrated. Through photo-fixation of Ag (I) ions with varied concentration (10-2 - 10-4 M) in the water phase under UV illumination, the films are subsequently surface-modified with Ag co-catalyst layers. Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), Ultraviolet-Visible (UV) Spectroscopy, and Electron Paramagnetic Resonance (EPR) techniques are used to physically characterize the samples. Results reveal that the modification of the co-catalyst had no impact on the thickness and porosity of the films. In addition, the study show that the modified TiO2 films had increased photocatalytic activity. All the characterization methods used have shown the formationof surface - bound Ag (I) species and metallic silver nanoclusters. By measuring the Methylene Blue (MB) dye degradation under UV light illumination, as - prepared and Ag -modified TiO2 films are evaluated for their photocatalytic activity, and the impact of the silver precursor concentration during photo-fixation is investigated.The highest catalytic activity is seen for films that have been modified at a concentration of Ag (I) of 10-2 M. Ordered from highest to lowest, the MB photodegradation rate constants are TiO2 < TiO2 /Ag, 10-4 < TiO2 /Ag, 10-3 < TiO2 / Ag, 10-2.

Photocatalytic activity enhancement of g-C3N4 nanosheets through simultaneous inter- and intra-layer charge separation using a facile mechano-thermal method

Herein, a novel mechano-thermal approach has been proposed to tune the electronic structure and enhance the photocatalytic performance of g-C3N4 nanosheets. According to the results, the high-energy ball-milling method modified the role of the ammonium chloride from the blowing agent to the doping agent, leading to the introduction of the interstitial and substitutional Chlorine (Cl) atoms into the nanosheet structure. Such a modification not only promoted electron-hole separation through the inter- and intra-layer of the g-C3N4 nanosheets, but it also led to the band gap energy reduction and higher oxidation capability of the photogenerated holes. These key improvements have been reflected in the optimized sample with a high-energy ball-milling time of 15 min (g-C3N4–15). Compared to the sample without the ball-milling process, g-C3N4–15 exhibited simultaneous intra- and inter-layer charge separation, reduction in the band gap energy from 2.82 to 2.76 eV, and positive shift in the valence band. Furthermore, these modifications in the electronic structure of the nanosheets contributed to the outstanding photocatalytic performance of the g-C3N4–15 towards methylene blue (MB) photodegradation. Among the samples with different ball-milling times, g-C3N4–15 demonstrated the highest MB photodegradation rate constant (0.0125 min−1), approximately 9 times greater than the sample without the ball-milling process. Additionally, the proposed photodegradation pathway suggested that the positive shift in the valence band of g-C3N4–15 could activate hydroxyl radicals (.OH) and promote demethylation and ring-opening of MB dyes.

Simultaneous preparation of ZnO/rGO composites through Zn(OH)2 decomposition and graphite oxide reduction and their photocatalytic properties.

ZnO/reduced graphite oxide (rGO) composites were simultaneously prepared by the thermal reduction of graphite oxide (GO) and the decomposition of Zn(OH)2. The samples were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence, and DRS. Results indicate that Zn(OH)2 was heated and decomposed into ZnO at a low temperature (200 ℃), while GO was reduced to graphene. The synthesized ZnO particles were small and loaded on graphene layers. The ZnO/rGO photocatalysts exhibited excellent photocatalytic activity against methylene blue (MB) under simulated sunlight irradiation. The ZnO/50% rGO photocatalyst showed the best MB photodegradation rate of up to 99.7% within 3min. Synchronous reaction provided an efficient, simple, and fast preparation method for ZnO/rGO composites, with an excellent solar photocatalytic degradation ability.

Rational design of coaxial CdS@ZnO nanowire array for efficient photodegradation of organic pollutants

Herein, a novel coaxial CdS@ZnO nanowire array catalyst was synthesized by magnetron sputtering and hydrothermal method. The optimum photocatalytic composite was obtained by controlling the ratio of CdS and ZnO. Take methylene blue (MB) as the model, the CdS@ZnO nanowire array (CdS@ZnO-10) exhibited strong photocatalytic solid activity, and the highest adsorption and photodegradation rate of MB reached 90.38 % in 50 min and 99.13 % in 120 min under simulated sunlight illumination. The mechanism of the heterojunction interface affecting photocatalytic performance was studied. Therefore, the synthesis approach could offer new design and controllable construction of coaxial structure for organic dye pollutant degradation.

Hydrothermal synthesis of Zn-doped brookite TiO2 for enhanced visible-light-responsive photocatalytic performance

Brookite TiO2 is considered as one of the excellent candidates in photo- or photo-/electro- chemical applications due to its unique crystalline structure and electronic properties. To achieve an enhanced visible-light-responsive brookite TiO2 photocatalyst, Zn-doped brookite TiO2 (ZBT) was in situ synthesized under hydrothermal conditions at 180 °C for 2 h in this research. X-ray diffraction (XRD) verified that the undoped sample was single-phase brookite TiO2, while the ZBT samples are mixtures of brookite and anatase because the incorporation of Zn caused brookite to anatase phase transformation. The average particle size of the ZBT samples was smaller than pure brookite TiO2 and decreased with the increase of Zn amount, indicating that Zn doping inhibited the growth of crystallite. ZBT samples exhibited better photocatalytic activity for the degradation of methylene blue (MB) than pure brookite TiO2 under visible light irradiation due to the effective separation of electrons and holes by Zn doping. Among the ZBT samples, the 5% ZBT sample exhibited the best photodegradation rate of MB (92.6%) under visible-light irradiation for 2 h, which was attributable to its small particle size (19.78 nm) and the large surface area (67.08 m−2 g−1).

Gd-doped BiVO4 microstructure and its composite with a flat carbonaceous matrix to boost photocatalytic performance

Fabrication of semiconductor-based photocatalysts with excellent charge separation efficiency has gained substantial attention due to their notable performance for water treatment applications. Herein, we synthesized a flat reduced graphene oxide-based gadolinium-doped bismuth vanadate (rGO/Gd/BiVO 4 ) composite by a facile hydrothermal and ultra-sonication approach. By examining the photodegradation of Methylene Blue (MB) dye from an aqueous solution under visible light, we compared the photocatalytic behavior of the rGO/Gd/BiVO 4 composite to that of pristine BiVO 4 and Gd/BiVO 4 . The photo-excited electron/hole pair recombination was suppressed by adding Gd and rGO to BiVO 4 . This led to rGO/Gd/BiVO 4 having a faster rate (k = 0.027 min −1 ) of MB degradation than Gd/BiVO 4 (k = 0.0095 min −1 ) and pure BiVO 4 (k = 0.006 min −1 ). In particular, the rGO/Gd/BiVO 4 degraded almost 97% of the MB dye under visible-light irradiation in 100 min, whereas the BiVO 4 and Gd/BiVO 4 samples removed only 53% and 69% of the MB dye, respectively. The rGO/Gd/BiVO 4 composite displayed 16-fold and 2.40-fold larger transient photocurrent responsiveness than the BiVO 4 and Gd/BiVO 4 samples. Subsequently, the BiVO 4 and Gd/BiVO 4 showed a charge recombination rate of 2.18 and 3.62 s, separately, which was relatively smaller than the rGO/Gd/BiVO 4 result (= 8.41 s). The increased photocatalytic activity of rGO/Gd/BiVO 4 is due to the development of heterojunction between Gd/BiVO 4 and the rGO sheets, which facilitates the absorption of photons as well as the separation of photogenerated electrons and holes. • Novel visible-light-driven rGO/Gd/BiVO 4 nanocomposite was fabricated by hydrothermal and facile ultrasonication approaches. • The photocatalytic performance of all the prepared materials was assessed by studying their MB dye degradation aptitude. • Approximately 97% MB dye molecules were degraded after 100 min of visible light irradiation over rGO/Gd/BiVO 4 photocatalyst. • rGO/Gd/BiVO 4 sample showed slower charge recombination, and larger MB photodegradation rate than pure BiVO 4 and Gd/BiVO 4 .

Functionalization of TiO2 inverse opal structure with atomic layer deposition grown Cu for photocatalytic and antibacterial applications

TiO2 inverse opal (IO) structure surfaces were functionalized with a sub-monolayer amount of Cu by atomic layer deposition (ALD) and tested for photocatalytic and antimicrobial applications. Decomposition of acetylene (C2H2) into CO2 and reduction of CO2 into CH4 were tested in the gas phase and photodegradation of methylene blue (MB) was tested in the liquid phase. Antimicrobial activity was tested against Gram-positive Staphylococcus aureus (S. aureus) bacteria. ALD Cu without any post-deposition heat treatment (HT) decreased the photo degradation rate of both C2H2 and MB but improved the activity towards CO2 reduction. ALD Cu increased MB photodegradation rate and antimicrobial activity only after HT at 550 °C, which was linked to the improved chemical stability Cu after the HT. The same HT decreased the activity towards CO2 reduction and decomposition of C2H2. The HT induced desorption of loosely bound ALD Cu+/2+ from the TiO2 IO surface and the remaining Cu+/2+ was reduced to Cu+. The photocatalytic and antimicrobial activity of TiO2 IO can be tailored by the addition of a sub-monolayer amounts of Cu with performance depending on the targeted reaction.

Photocatalytic degradation of MB by novel and environmental ZnO/Bi2WO6-CC hierarchical heterostructures

ZnO-CC and ZnO/Bi2WO6-CC with different Bi2WO6 loadings layered heterostructures photocatalysts were synthesized on flexible carbon clothes (CC) substrate by the thermal decomposition-hydrothermal method. By characterizing the degradation of methylene blue (MB) under ultraviolet light irradiation, Z3B-CC (3 wt% Bi2WO6) showed the best photocatalytic effect, and the photodegradation rate of MB was as high as 96.9% in about 100 min. This new ZnO/Bi2WO6-CC layered heterostructure exhibits prominent photocatalytic performance, which is mainly ascribed to the type II band structure formed by ZnO and Bi2WO6. The appropriate energy band position further facilities the effective transfer of carriers and realizes the photocatalytic process of the heterostructure. This study is prospective to provide new ideas for the synthesis of other high-efficiency heterostructure photocatalytic designs, and it also has reference value for the synthesis of flexible photocatalytic materials with excellent performance.

Review on Methylene Blue: Its Properties, Uses, Toxicity and Photodegradation

The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

Synthesis and Photocatalytic Activity of Hexagonal Plate-like Shaped Au Nanoparticles/ZnO Composite Particles under Visible-light Irradiation.

We synthesized Au nanoparticle (AuNP)/ZnO composite particles in presence of an anionic surfactant and evaluated their photocatalytic activity under visible-light irradiation. AuNPs synthesized from HAuCl4 in the presence of amylase and the precursor solutions of ZnO were mixed, followed by a hydrothermal process, to synthesize crystal face-controlled AuNP/ZnO composite particles. X-ray diffraction (XRD) patterns and ultraviolet-visible (UV-Vis) spectra confirmed the formation of AuNP/ZnO composite particles. Furthermore, different Au to Zn concentration ratios in the precursor solutions resulted in different amounts of AuNPs in the composite particles. In addition, the average size of the AuNP/ZnO composite particles decreased with increasing Au to Zn concentration ratio. We believe AuNPs act as the nuclei for ZnO particle formation. The photocatalytic activity of the AuNP/ZnO composite particles was evaluated by the photodegradation of methylene blue (MB) under visible-light irradiation. The photodegradation rate of MB was higher with AuNP/ZnO composite particles compared to that with the ZnO particles synthesized in the absence of AuNPs. The AuNP/ZnO composite particles exhibit photocatalytic activity under visible-light irradiation owing to the enhanced charge separation efficiency and the localized surface plasmon resonance effect.

Preparation and photocatalytic properties of nanocrystalline ZnWO4/TiO2

In order to combine ZnWO4 and TiO2 to form a heterojunction, a sol–gel method combined with a hydrothermal method was used to synthesize a ZnWO4/TiO2 heterojunction to degrade methylene blue (MB). The phase composition, microstructure, and photocatalytic performance of the synthesized catalysts are researched. The experimental results show that the sample with the TiO2:ZnWO4 ratio of 1:2 exhibited rod-shaped morphology with a size of about 100 nm, and the heterojunction structure is formed at the interface of zinc tungstate and titanium dioxide. The sample with the TiO2:ZnWO4 ratio of 1:3 is composed of zinc tungstate, titanium dioxide with poor crystallinity and ZnTiO3 impurities, presenting a rod-like structure formed by agglomeration of particles. Compared with pure zinc tungstate and titanium dioxide, the nanocrystalline TiO2:ZnWO4 has a higher photodegradation rate. The sample with the TiO2:ZnWO4 ratio of 1:2 has the best photocatalytic performance, and the photodegradation rate of MB reaches 94.6%. The sample with the TiO2:ZnWO4 ratio of 1:3 has better adsorption characteristics, but the photodegradation rate decreases.

Preliminary Study of ZnO/GO Composite Preparation as Photocatalyst Material for Degradation Methylene Blue under Low UV-Light Irradiation

ZnO:Graphene Oxide composite nanopowders have been successfully prepared by sol-gel method. The study of composite preparation is discussed in this paper. Graphene oxide was added in two ways in order to study the mixed behaviour especially in photocatalytic properties. The degradation of methylene blue (MB) concentration in water was used to evaluate the photocatalytic property under low UV-light irradiation (14 μW/cm2). The results showed that all varian ZnO-GO composite samples have spherical morphology and hexagonal wurtzite crystal structure. An addition of graphene oxide (GO) in ZnO precursor solution during preparation shows a better photocatalytic property that related to reducing in particle size, thereby produce a large surface area and formed a better interfacing with GO/rGO. The existence of GO around ZnO nanoparticles gives some advantageous due to presences of hydroxyl component that directly relate to the increments in photocatalytic behavior. The photodegradation rate of MB in water using ZnO-GO composite as catalyst is significantly increase compared with pure ZnO.

A ternary CdS/AgBr/Ag3PO4 nanocomposite: characterization and the kinetics of its photocatalytic activity.

A ternary CdS/AgBr/Ag3PO4 coupled system was prepared, characterized by different techniques, and used for the photodegradation of methylene blue (MB). The hexagonal (wurtzite) CdS, the cubic AgBr, and the Ag3PO4 body-centered cubic crystallite phases were detected by XRD patterns. The Scherer equation showed the crystallite sizes of 3, 26.3, 28, and 27.9 nm for CdS, Ag3PO4, AgBr NPs, and the ternary CdS/AgBr/Ag3PO4 sample, while the Williamson-Hall model got the values of 1.8, 46.2, 62.12, and 92.44 nm, respectively. The diffuse reflectance spectra (DRS) showed that the ternary catalyst could absorb the whole range of visible light photons. The photoluminescence (PL) spectra significantly depended on the solvent nature, and the sharp scattering peaks appeared in the water, while these were absent in acetone as solvent. The ternary catalyst also showed a lower PL intensity and a higher photocatalytic activity concerning the individual NPs. When the moles of CdS were three times greater than the other components, the resulted ternary catalyst showed the lowest PL intensity and the highest degradation activity. The MB mineralization was also studied by the COD technique and compared with MB photodegradation kinetically. The MB photodegradation rate constant of about 0.0276 min-1 (correspond to t1/2 25.1 min) was 1.75 times greater than the MB mineralization rate constant (about 0.0158 min-1 correspond to t1/2 value of 43.9 min).

An excellent Z-scheme Ag2MoO4/Bi4Ti3O12 heterojunction photocatalyst: Construction strategy and application in environmental purification

Herein we have designed an excellent type of Z-scheme Ag2MoO4/Bi4Ti3O12 (AMO/BTO) heterojunction photocatalysts by immobilizing AMO particles onto rod-like BTO hierarchical architectures. The formation of Z-scheme AMO/BTO heterostructures was verified by various characterization techniques including XRD, UV–vis DR spectroscopy, SEM, TEM, XPS and FTIR spectroscopy. PL spectroscopy, photocurrent response and EIS analyses suggest that the creation of AMO/BTO heterojunctions is conducive to the efficient separation of photoexcited electron-hole pairs. The photocatalytic performances of the AMO/BTO composites were investigated by simulated-sunlight driving photodegradation of methylene blue (MB), tetrabromobisphenol A (TBBPA), tetracycline hydrochloride (TC), phenol and methyl orange (MO)/rhodamine B (RhB)/MB mixture solutions. It is demonstrated that the AMO/BTO heterojunction photocatalysts are endowed with excellent photodegradation performances much higher than that of bare AMO and BTO. For example, the photodegradation rate of MB by using 30 wt%AMO/BTO — confirmed to be the optimal composite sample — is about 17.0 and 14.7 times as high as that by using bare BTO and AMO, respectively. A Z-scheme electron transfer mechanism was proposed to elucidate the enhanced photodegradation performances of the AMO/BTO heterojunction photocatalysts.

Visible light photocatalytic degradation of methylene blue by hydrated titanium dioxide nanoparticles incorporated within rice straw

A novel photocatalyst was successfully synthesized by immobilizing hydrated titanium dioxide (HTO) nanoparticle within rice straw (RS) via a sol–gel method. The HTO nanoparticles were successfully loaded onto the surface of RS confirmed by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and Brunauer–Emmett–Teller (BET) model. Through Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR), the formed C–O–Ti bond in RS-HTO gave rise to a strong link and, hence, the charge transportation rate was improved. In the photocatalytic processes, the recombination of electrons and holes was smothered. In addition, thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) proved RS-HTO had good thermal stability. The photocatalytic activity of RS-HTO nanocomposites was measured by the photo-degradation performance of methylene blue (MB) solution under visible light. The study showed that the photo-degradation rate of MB could reach 95.18%, which was higher than RS (approximately 20%). Meanwhile, based on experiment (ESR), MB was degraded by hydroxyl radicals (·OH). These results demonstrated that HTO nanoparticle within RS was an effective method for dyestuffs wastewater treatment.

Facet-Dependent Photodegradation of Methylene Blue by Hematite Nanoplates in Visible Light.

The expression of specific crystal facets in different nanostructures is known to play a vital role in determining the sensitivity toward the photodegradation of organics, which can generally be ascribed to differences in surface structure and energy. Herein, we report the synthesis of hematite nanoplates with controlled relative exposure of basal (001) and edge (012) facets, enabling us to establish direct correlation between the surface structure and the photocatalytic degradation efficiency of methylene blue (MB) in the presence of hydrogen peroxide. MB adsorption experiments showed that the capacity on (001) is about three times larger than on (012). Density functional theory calculations suggest the adsorption energy on the (001) surface is 6.28 kcal/mol lower than that on the (012) surface. However, the MB photodegradation rate on the (001) surface is around 14.5 times faster than on the (012) surface. We attribute this to a higher availability of the photoelectron accepting surface Fe3+ sites on the (001) facet. This facilitates more efficient iron valence cycling and the heterogeneous photo-Fenton reaction yielding MB-oxidizing hydroxyl radicals at the surface. Our findings help establish a rational basis for the design and optimization of hematite nanostructures as photocatalysts for environmental remediation.

Liquid phase deposition of flower-like TiO2 microspheres decorated by ZIF-8 nanoparticles with enhanced photocatalytic activity

Abstract In this study, the liquid phase deposition of flower-like TiO2 microspheres were decorated by ZIF-8 nanoparticles, forming the ZIF-8/TiO2 composite materials. The results showed that the ZIF-8 nanoparticles can be well-deposited on the surface of TiO2 microspheres with a porous microstructure. The photocatalytic activity of the as-prepared materials were evaluated by the degradation of methylene blue (MB) and rhodamine B (RhB) solutions. It revealed that the ZIF-8/TiO2 composite materials exhibited the enhanced photocatalytic activity, of which the photodegradation rate of MB and RhB solutions with initial concentration of 10 mg/L can reach approximately 90% under illumination for 40 min. Moreover, the reactive species trapping experiments indicated that ·OH was the main active species during the photodegradation process in this system. The enhanced photocatalytic activity of ZIF-8/TiO2 composite materials was attributed to the synergistic effect between the TiO2 microspheres and ZIF-8 nanoparticles, which resulted in the increased specific surface area and the reduced recombination of photogenerated charge carriers.

Femtosecond laser mediated fabrication of micro/nanostructured TiO2-x photoelectrodes: Hierarchical nanotubes array with oxygen vacancies and their photocatalysis properties

Titanium dioxide (TiO2) photoelectrodes that offer high light absorption and efficient charge separation hold great promise in photocatalysis. In this study, a simple and controllable method for fabricating hierarchical TiO2−x photoelectrodes by coupling femtosecond laser processing and anodization is proposed. The fabricated photoelectrodes consist of microcones (approximately 150,000 per square centimetre) covered with large quantities of nanotubes. The hierarchical structures possess significant light-trapping effect, meanwhile, oxygen vacancies were simultaneously introduced through laser processing with anodization, which can be attributed to the fs-laser mediated lattice phase transformation (polycrystalline and amorphous layer) of titanium. With the synergistic effects of hierarchical structures and oxygen vacancies, the hierarchical TiO2−x electrode exhibited a narrowed bandgap (1.95 eV) and remarkable light absorption. Especially under visible light, this photoelectrode demonstrated 15-fold photocurrent enhancement and double the usual photodegradation rate of methylene blue. This morphological control and defect introduction method may be extensively used in efficient solar utilisation.

Effect of sprayed volume on physical properties of Cu2FeSnS4 thin films and an efficient p-type Cu2FeSnS4/n-type F-doped SnO2 heterojunction

Quaternary chalcogenide Cu2FeSnS4 (CFTS) thin layers were successfully synthesized by a spray pyrolysis technique and deposited on glass substrates for different sprayed volumes (Vs = 300, 600, 900, and 1200 ml). Energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy, X-ray diffraction (XRD), Raman spectroscopy, spectrophotometry, and Hall effect measurements were used to investigate, respectively, the chemical composition and the morphological, structural, optical, and electrical properties of CFTS thin films. XRD analysis and Raman spectroscopy revealed that the optimum growth of CFTS thin film occurred for Vs = 900 ml owing to the pure phase, good crystallinity, and maximum crystallite size estimated to be 62 nm. EDX analysis for Vs = 900 ml showed that the Cu/Fe/Sn/S stoichiometric ratio is close to the theoretical value of 2:1:1:4. The band gap and the electrical resistivity of the optimum film are 1.48 eV and 0.11 Ω cm, respectively. These experimental results allow us to consider CFTS thin film prepared with Vs = 900 ml as a promising absorber layer for solar cell applications. Furthermore, the optimum CFTS thin film exhibits good photocatalytic activity toward the degradation of methylene blue under sunlight irradiation. Moreover, a new heterojunction composed of CFTS and F-doped SnO2 was synthesized and studied. The photodegradation rate of methylene blue was 88%, which makes this heterojunction a promising alternative for removal of organic pollutants in wastewater treatment by photocatalysis.

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

In this study, a magnetically recyclable Ni1-xCdxCeyFe2-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 Ni1-xCdxCeyFe2-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.