Precipitation dispersion of various ratios of BiOI/BiOCl nanocomposite over g-C 3 N 4 for promoted visible light nanophotocatalyst used in removal of acid orange 7 from water

Construction of 2D/3D g-C3N4/BiOI Photocatalysts with p-n Heterojunction and Their Performance in Photocatalytic Degradation of Amaranth Dye

The g-C3N4 (graphitic carbon nitride)/BiOI (bismuth oxyiodide) photocatalysts, boasting a unique nanomicrosphere architecture, were synthesized through a tripartite process involving heat polycondensation, hydrothermal treatment, and hybrid methods, using melamine, bismuth nitrate, and potassium iodide as starting materials. The photocatalyst was comprehensively characterized and analyzed while its efficacy in photocatalytic degradation of amaranth (AR) under various lighting conditions was investigated, and the catalytic mechanism was determined by kinetic analysis and free radical scavenging experiments. The results showed that g-C3N4 formed a strong bond with BiOI. The resulting composite catalyst retains the inherent 2D lamellar structure of g-C3N4, as well as the 3D microsphere structure of BiOI, thereby creating heterojunctions via p-n interactions. Under visible light exposure, g-C3N4/BiOI-15% demonstrated optimal catalytic performance, achieving a degradation rate of 74.64% for AR and exhibiting the highest rate constant. Radical tests confirmed that -O2- (superoxide anion) plays a crucial role as active species in the photocatalytic reaction.

G-C3N4-Ag composite mediated photocatalytic degradation of phenanthrene - A remedy for environmental pollution

In recent years, g-C3N4-Ag nanocomposite synthesis has gained considerable attention for its potential to treat polycyclic aromatic hydrocarbons (PAHs) and to act against bacteria and fungi. In this study, we present a novel approach to the synthesis of g-C3N4-Ag nanocomposite and evaluate its efficiency in both PAH removal and antimicrobial activity. The synthesis process involved the preparation of g-C3N4 by thermal polycondensation of melamine. The factors that affect the adsorption process of PAHs, like time, pH, irradiation type, and adsorbent dosage, were also evaluated. Isotherm models like Langmuir and Freundlich determined the adsorption capability of g-C3N4-Ag. In simulated models, phenanthrene was degraded to a maximum of 85% at lower concentrations of catalyst. The adsorption profile of phenanthrene obeys the pseudo-second-order and Freundlich isotherms pattern. The g-C3N4-Ag nanocomposite also exhibited antimicrobial activity against bacteria (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae) and fungi (Candida albicans). The present study is the first report stating the dual application of g-C3N4-Ag nanocomposite in reducing the concentration of PAH and killing bacterial and fungal pathogens. The higher adsorption capability proclaimed by g-C3N4-Ag nanocomposite shows the fabricated nanomaterial with great potential to remediate organic pollutants from the ecosystem.

Plasmonic-driven charge separation through combining Ag nanoparticles (Ag NPs) to form a double Z-scheme heterostructure in WO3/BiOCl/g-C3N4 for the photocatalytic degradation of antibiotics

Integrating a heterojunction system with the impact of surface plasmon resonance (SPR) is an executable and innovative tactic for photocatalyst amelioration. Ag nanoparticle (Ag NP)-modified WO3/BiOCl/g-C3N4 (WB-CN) was favorably fabricated through in situ photo deposition assembly to form double heterojunctions (A-WBCN). The degradation performance of A-WBCN is better than that of pure g-C3N4 (CN) and WO3/BiOCl (WB), it can degrade more than 90% of OFLX within 20 minutes, due to Ag NPs performing as a bridge for electron mediators, apart from the implications of SPR in A-WBCN. The results of UV diffuse reflectance spectroscopy indicate that loading with Ag NPs can expand the light absorption range of WB-CN to near-infrared. The photoluminescence spectra and transient photocurrent spectra indicate that Ag NP loading significantly improves the separation efficiency of photogenerated carriers. Density functional theory (DFT) simulation results show that the introduction of Ag NPs can change the direction of carrier movement, resulting in bending of the energy bands of WB and CN, improving the redox ability of A-WBCN, and improving its photocatalytic efficiency. In addition, the intermediate products of OFLX was determined by HPLC-MS analysis. The spin electron resonance (ESR) results indicate that ˙O2- and ˙OH are the main active species in photocatalytic degradation. This work furnishes a fresh idea for upgrading photocatalytic performance and advancing electron transfer.

Comparative Analysis of the Interfacial Structure and Properties of BiOX/BiOY (X, Y = F, Cl, Br, and I) Heterostructures through DFT Calculations

This study focuses on the systematic investigation of the microstructure, interfacial energy, and electronic structure of six BiOX/BiOY heterostructures constructed using four bismuth oxyhalide materials. Utilizing density functional theory (DFT) calculations, the study provides fundamental insights into the interfacial structure and properties of these heterostructures. The results indicate that the formation energies of BiOX/BiOY heterostructures decrease in the order of BiOF/BiOI, BiOF/BiOBr, BiOF/BiOCl, BiOCl/BiOBr, BiOBr/BiOI, and BiOCl/BiOI. BiOCl/BiBr heterostructures were found to have the lowest formation energy and were the most easily formed. Conversely, the formation of BiOF/BiOY heterostructures was observed to be unstable and difficult to achieve. Furthermore, the interfacial electronic structure analysis revealed that BiOCl/BiOBr, BiOCl/BiOI, and BiOBr/BiOI displayed opposite electric fields that facilitated electron-hole pair separation. Therefore, these research findings provide a comprehensive understanding of the mechanisms underlying the formation of BiOX/BiOY heterostructures and present theoretical guidance for the design of innovative and efficient photocatalytic heterostructures, with an emphasis on BiOCl/BiOBr heterostructures. This study highlights the advantages of distinctively layered BiOX materials and their heterostructures, which offer a wide range of band gap values, and demonstrates their potential for various research and practical applications.

Fabrication of an effectual, stable and reusable Mg-doped CdAl2O4 nanoparticles for photodegradation of toxic pollutants under visible light illumination

The water contamination caused by discharging extensive organic dyes stuff into water bodies is one of the utmost significant concerns disturbing the environment and human life. CdAl₂O₄ spinel materials have been excellent in the elimination of emerging pollutants by the photocatalysis route. These materials, when altered through methods namely doping with Mg ions, have benefits over CdAl₂O₄, especially reduced energy gap and light absorbed in the visible region. The XRD established the creation of space group R 3‾ with no other phase step being found. The photoluminescence outcomes indicated that Mg-doped CdAl₂O₄ nanoparticles had the preventing e^--h⁺ recombination possibility, which was favorable for the photocatalytic process. The Mg (0.075 M)-doped CdAl₂O₄ catalyst had higher photocatalytic performance with 94 and 96% removal of two azo (BB and BG) dyes under a mere 90 min visible light irradiation, which indicated enhanced Photodegradation behaviors when compared to other Mg (0.025, 0.050 M)-doped and pure CdAl₂O₄ materials. More interestingly, pH 5 was optimum for the Mg (0.075 M)-doped CdAl₂O₄ samples photodegradation of both dyes, and the optimum catalyst amount was 5 mg/100 mL. The doped Mg ions influenced the elimination of both dyes by inducing the manufacture of more active species. The Mg (0.075 M)-doped CdAl₂O₄ samples is reusable and highly stable with only a 5% reduction in degradation rate after six cycles. Based on the quencher and ESR investigations, the ^.OH^- and h⁺ are described as active species in the removal reaction. We hope our present examinations highlight the possibility of using Mg (0.075 M)-doped CdAl₂O₄ product for a broad range of photodegradation applications, also it may be applied for several ecological remediations, surface cleaning devices, foods and pharmaceutical industry applications.

Efficient removal of plastic additives by sunlight active titanium dioxide decorated Cd-Mg ferrite nanocomposite: Green synthesis, kinetics and photoactivity

Large use of flame retardants or additives in plastic industries have caused scientific attention as their leaching from consumer products is indicative of environmental concern. Moreover, plastic additives have proven features of endocrine disruptors, genotoxicity and persistence. Therefore, photodegradation of tetrabromobisphenol A (TBBPA) and bisphenol A (BPA) were explored in water. Seeing environmental safety, titanium dioxide decorated magnesium substituted cadmium ferrite (CdMgFe₂O₄@TiO₂) was synthesized by using plant extract of M. koenigii via co-precipitation. Sharp peaks obtained in PXRD ensured high crystallinity and purity of distorted spherical nanocomposite (5-25 nm). Subsequently, CdMgFe₂O₄@TiO₂ nanocatalyst was evaluated for the effective elimination of plastic additives at variable reaction parameters (pollutant: 2-10 mgL^-1; catalyst: 5-25 mg; pH: 3-7, dark-sunlight). With 20 mg of catalytic dose, CdMgFe₂O₄@TiO₂ showed maximum degradation of 2 mgL^-1 of TBBPA (91%) and BPA (94%) at neutral pH under sunlight. Considerable reduction in persistence of TBBPA (t_1/2:2.4 h) and BPA (t_1/2:2.1 h) indicated admirable photoactivity of CdMgFe₂O₄@TiO₂. Results were supported by BET, zeta potential, band reflectance and photoluminescence analysis that indicated for higher surface area (90 m²g^-1), larger particle stability (-20 mV), lower band gap (1.9 eV) and inhibited charge-pairs recombination in nanocomposite. Degradation consisted of initial Langmuir-adsorption followed by first order kinetics. Scavenger analysis revealed the role of hydroxyl radical in photodegradation studies. Nanocomposite was effective up to eight cycles without any significant loss of activity that advocated its high-sustainability and cost-effectiveness. Overall, with excellent surface characteristics, green synthesized CdMgFe₂O₄@TiO₂ nanocomposite is a promising and alternative photocatalyst for industrial applications.

Self-Assembled Silver Nanoparticles Decorated on Exfoliated Graphitic Carbon Nitride/Carbon Sphere Nanocomposites as a Novel Catalyst for Catalytic Reduction of Cr(VI) to Cr(III) from Wastewater and Reuse for Photocatalytic Applications

Silver nanoparticles decorated on an exfoliated graphitic carbon nitride/carbon sphere (AgNP/Eg-C₃N₄/CS) nanocomposites were synthesized by an adsorption method with a self-assembled process. These nanoparticles were characterized by different techniques like UV-visible (UV-vis) spectroscopy, photoluminescence (PL) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Raman spectroscopy, scanning electron spectroscopy (SEM), transmission electron spectroscopy (TEM), electrochemical impedance spectroscopy (EIS), and ζ potential. AgNP/Eg-C₃N₄/CS nanocomposites showed a higher catalytic reduction activity for the conversion of Cr(VI) into Cr(III) with formic acid (FA) at 45 °C when compared to bulk graphitic carbon nitride (Bg-C₃N₄, Eg-C₃N₄, CS, and Eg-C₃N₄/CS). The kinetic rate constants were determined as a function of catalyst dosage, concentration of Cr(VI), pH, and temperature for the AgNP/Eg-C₃N₄/CS nanocomposite. This material showed higher reduction efficiency (98.5%, k = 0.0621 min^-1) with turnover frequency (0.0158 min^-1) for the reduction of Cr(VI) to Cr(III). It also showed great selectivity and high stability after six repeated cycles (98.5%). Further, the reusability of the Cr(III)-AgNP/Eg-C₃N₄/CS nanocomposite was also investigated for the photocatalytic degradation of methylene blue (MB) under visible light irradiation with various time intervals and it showed good degradation efficiency (α = 97.95%). From these results, the AgNP/Eg-C₃N₄/CS nanocomposite demonstrated higher catalytic activity, improved environmental friendliness, lower cost for the conversion of toxic Cr(VI) to Cr(III) in solutions, and also good reusability.

Efficient degradation of organic pollutants by novel titanium dioxide coupled bismuth oxide nanocomposite: Green synthesis, kinetics and photoactivity

Herein, a green and facile methodology was used for the structural design of semiconductor nanomaterials and employed as efficient photocatalyst to resolve the environmental issues of water pollutants. Titanium oxide coupled with bismuth oxide (TiO₂@Bi₂O₃) nanocomposite was synthesized by employing the seed extract of Sapindus mukorossi (commonly found plant in India) and subsequently used for the elimination of toxic, and persistence industrial pollutants namely bisphenol A (BPA) and methylene blue (MB). Microscopic and spectroscopic techniques revealed particle size of synthesized nanocomposite found less than 50 nm along with high crystallinity. Appearance of stretching vibrations at 459 cm^-1 for Bi-O-Ti in the IR spectra of nanocomposite has established the coupling of TiO₂ with Bi₂O₃. The parameters of degradation were optimized by varying the pollutant concentration, catalytic amount and pH in the presence of natural sunlight. The nanocomposite TiO₂@Bi₂O₃ showed maximum degradation (MB: 94% and BPA: 91%) at a minimum concentration of pollutant (50 mgL^-1) with catalyst amount (35 mg), neutral pH and reduces half-life of pollutants (BPA: 1h, MB: 0.5h). Owing of higher surface area (80 m²g^-1), lower band gap (2.5 eV), and more negative zeta potential value (-40.3 mV) results into excellent photocatalytic properties. The breakage of S-N conjugated system in MB results into rapid degradation as compare to BPA. The degradation followed first-order kinetics and Langmuir adsorption in both the cases. Presence of active radicals during the photocatalysis process was responsible for quick degradation and strongly supported by scavenger analysis. GC-MS analysis revealed the degradation of toxic pollutants into safer metabolites and finally mineralized. Multiple times (n = 8) reusability of green photocatalyst advocated sustainability and appropriate for industrial applications.

Recent developments on bismuth oxyhalides (BiOX; X = Cl, Br, I) based ternary nanocomposite photocatalysts for environmental applications

Photocatalytic treatment of organic pollutants present in wastewater using semiconductor nanomaterials under light irradiation is one of the efficient advanced oxidation processes. Stable metal oxide (e.g. TiO₂) based semiconductor photocatalytic systems have been mainly investigated for this purpose. Nevertheless, their large band gap (~3.2 eV) makes them inefficient in utilization of visible light portion of solar light leading to a lower degradation efficiency. Investigations have focused on the development of visible light responsive bismuth oxyhalides (BiOX; X = Cl, Br, I), one of the potential nanomaterials with unique layered structure, for efficient absorption of solar light for the degradation of pollutants. However, the rapid recombination rate of photogenerated charge carriers limits their practical applicability. To overcome such drawbacks, the development of BiOX based ternary nanocomposites received significant attention because of their unique structural and electronic properties, improved visible light response and increased separation and transfer rate of photogenerated charge carriers. This review aims to provide a comprehensive overview of the recent developments on bismuth oxyhalides-based ternary nanocomposites for enhanced environmental pollutants decomposition under visible light irradiation. The principles of photocatalysis, synthetic methodologies of bismuth oxyhalides and their characteristics such as heterojunctions formation, improved visible light response and separation rate of charge carriers and the mechanisms for enhanced visible light photocatalytic activity are discussed. In addition, the future prospects on the improvement in the photocatalytic activity of bismuth oxyhalides-based ternary nanocomposites are also discussed. This review could be beneficial for designing new ternary nanocomposites with superior visible light photocatalytic efficiency.

A Review: Photocatalysts Based on BiOCl and g-C3N4 for Water Purification

Many organic pollutants are discharged into the environment, which results in the frequent detection of organic pollutants in surface water and underground water. Some of the organic pollutants can stay for a long time in the environment due to their recalcitrance. Advanced oxidation processes (AOPs) can effectively treat the recalcitrant organic compounds in water. Photocatalysis as one of the AOPs has attracted a lot of interest. BiOCl and g-C3N4 are nice photocatalysts. However, their catalytic activity should be further improved for industrial utilization. The construction of heterojunction between the two different components is deemed as an efficient strategy for developing a highly efficient photocatalyst. As a typical type-II heterojunction, g-C3N4/BiOCl heterojunctions showed better photocatalytic performance. To date, the g-C3N4/BiOCl composites were mainly studied in the field of water purification. The photoactivity of the pristine catalysts was greatly enhanced by the combination of the two materials. However, three kinds of proposed mechanisms were used to explain the improvement of the g-C3N4/BiOCl heterojunctions. But few researchers tried to explain why there were three different scenarios employed to explain the charge transfer. According to the articles reviewed, no direct evidence could indicate whether the band structures of the heterojunctions based on BiOCl and g-C3N4 were changed. Therefore, many more studies are needed to reveal the truth. Having a clearer understanding of the mechanism is beneficial for researchers to construct more efficient photocatalysts. This article is trying to start a new direction of research to inspire more researchers to prepare highly effective photocatalysts.

Integration of oxygen vacancies into BiOI via a facile alkaline earth ion-doping strategy for the enhanced photocatalytic performance toward indometacin remediation

Bismuth oxyiodide (BiOI) has garnered intense attention in the field of photocatalysis for environmental remediation; however, it suffers from a high electron-hole recombination rate. In this study, for the first time, we report on a facile strategy for the creation of oxygen vacancies in BiOI via strontium (Sr²⁺) doping. The as-prepared 0.45-SrBiOI demonstrated significantly enhanced photocatalytic degradation of indometacin under visible light exposure, which was almost 10 folds higher than pristine BiOI. This augmented photocatalytic performance was ascribed to the accelerated separation of charge carriers by oxygen vacancies, as well as Sr ion trapping electrons. Reactive species determination experiments revealed that O₂^▪-, ¹O₂, and h⁺ were the dominant active species. Finally, potential indometacin degradation pathways were proposed based on the identification of degradation by-products and theoretical calculations. This study offers new perspectives for the synthesis of highly efficient and cost effective BiOI-based photocatalysts, and provides a promising strategy toward advanced environmental remediation.

Advanced Two-Dimensional Heterojunction Photocatalysts of Stoichiometric and Non-Stoichiometric Bismuth Oxyhalides with Graphitic Carbon Nitride for Sustainable Energy and Environmental Applications

Semiconductor-based photocatalysis has been identified as an encouraging approach for solving the two main challenging problems, viz., remedying our polluted environment and the generation of sustainable chemical energy. Stoichiometric and non-stoichiometric bismuth oxyhalides (BiOX and BixOyXz where X = Cl, Br, and I) are a relatively new class of semiconductors that have attracted considerable interest for photocatalysis applications due to attributes, viz., high stability, suitable band structure, modifiable energy bandgap and two-dimensional layered structure capable of generating an internal electric field. Recently, the construction of heterojunction photocatalysts, especially 2D/2D systems, has convincingly drawn momentous attention practicably owing to the productive influence of having two dissimilar layered semiconductors in face-to-face contact with each other. This review has systematically summarized the recent progress on the 2D/2D heterojunction constructed between BiOX/BixOyXz with graphitic carbon nitride (g-C3N4). The band structure of individual components, various fabrication methods, different strategies developed for improving the photocatalytic performance and their applications in the degradation of various organic contaminants, hydrogen (H2) evolution, carbon dioxide (CO2) reduction, nitrogen (N2) fixation and the organic synthesis of clean chemicals are summarized. The perspectives and plausible opportunities for developing high performance BiOX/BixOyXz-g-C3N4 heterojunction photocatalysts are also discussed.

Fabrication of ternary AgBr/BiPO4/g-C3N4 heterostructure with dual Z-scheme and its visible light photocatalytic activity for Reactive Blue 19

A plasmonic photocatalyst of AgBr/BiPO₄/g-C₃N₄ was prepared. X-ray powder diffraction, Scanning electron microscope, Transmission electron microscopy, Fourier infrared spectroscopy, Ultraviolet Visible diffuse reflectance spectroscopy and photoluminescence emission spectra have been employed to determine the structure, morphology and optical property of the as-prepared AgBr/BiPO₄/g-C₃N₄ composite and analysis the reasons for improving photocatalytic efficiency. The optimal doping ratio of AgBr was 10 wt% by degrading 20 mg/L of Reactive Blue 19 (RB19) under visible light (λ > 420 nm), and 10 wt%AgBr/BiPO₄/g-C₃N₄ degraded 20 mg/L of RB19 to 2.59% at 40 min, which is ascribed to synergistic effects at the interface of AgBr, BiPO₄ and g-C₃N₄. The effect of catalyst dosage, initial concentration and initial pH of RB19 solution on photocatalytic efficiency was investigated. Four cycles of experiments were conducted. Finally, through the trapping experiment, we found that the main active factor for degrading RB19 in the photocatalytic process is O₂^-. The possible photocatalytic mechanism of AgBr/BiPO₄/g-C₃N₄ was discussed in connection with the synergistic effect of Ag and active substances at the AgBr/BiPO₄/g-C₃N₄ interface.

A hydrolysis synthesis route for (001)/(102) coexposed BiOCl nanosheets with high visible light-driven catalytic performance

The (001)/(102) co-exposed BiOCl nanosheet shows good adsorption of cationic dyes and high visible light-driven catalytic performance.

Understanding the effects of co-exposed facets on photocatalytic activities and fuel desulfurization performance in BiOCl singlet-crystalline sheets

Two kinds of well-crystallized BiOCl singlet-crystalline sheets (BOC-01 with twin-facet co-exposure of {001} and {110} and BOC-02 with tri-facet co-exposure of {001}, {110}, and {010}) were prepared and characterized. The photocatalytic desulfurization performance of BOC-01 and BOC-02 was tested by using n-decane and tetradecane as model oil containing heterocyclic sulfur-containing compounds (benzothiophene, or dibenzothiophene, or 4,6-dimethyldibenzothiophene). The desulfurization performance showed that twin-facet co-exposed BOC-01 had a slightly higher photocatalytic activity than tri-facet co-exposed BOC-02. The differences of photocatalytic activity between BOC-01 and BOC-02 were further explored by paramagnetic resonance spectroscopy, ultraviolet diffuse reflectance spectroscopy, steady-state and time-resolved prompt fluorescencespectra. The results disclosed that the exciton effect in BOC-01 played a key role in photocatalytic activation of molecular oxygen, while BOC-02 mainly produced reactive oxygen species by charge transfer. Theoretical calculations further indicated that the photogenerated electrons are mainly distributed on the {110} facets and the photogenerated holes are mainly distributed on the {001} facets in BOC-01 and BOC-02. This work provides a useful clue for an in-depth understanding of the effects of co-exposed facets in BiOCl on photocatalytic performance.

Hydrothermal synthesis of p-C3N4/f-BiOBr composites with highly efficient degradation of methylene blue and tetracycline

Construction of heterojunctions with band-suitable different semiconductors has been demonstrated to be an efficient approach to enhance the separation of photoinduced electrons and holes. In this paper, highly efficient heterojuction photocatalysts consisted of porous-C₃N₄ (p-C₃N₄) and flowerlike-BiOBr (f-BiOBr) were successfully synthesized via a deposition-hydrothermal method. The SEM and HRTEM images indicated that BiOBr were successfully deposited on the surface of p-C₃N₄ and the layered p-C₃N₄/f-BiOBr heterojunctions were formed between p-C₃N₄ and f-BiOBr. The optimum photocatalytic activity of the p-C₃N₄/f-BiOBr nanocomposites with weight ratio of 3%p-C₃N₄ exhibited dramatically improved visible-light photocatalytic activities with 98.42% and 94.25% degradation rates for methylene blue (MB) and tetracycline, respectively. The enhanced activity was mainly attributed to the unique heteojunction architecture, which creates large interfacial surface between the constituent materials for facilitating charge transfer and effectively inhibits the fast recombination of photogenerated electrons and holes. The active species trapping experiment indicated that the O₂^- was the dominating reactive oxidizing species of p-C₃N₄/f-BiOBr for MB degradation under visible light irradiation. Moreover, the as-prepared photocatalysts displayed excellent stability in the recycling experiments with no obvious decrease of the degradation efficiencies for MB and tetracycline. Furthermore, the possible photocatalytic degradation mechanism of MB over p-C₃N₄/f-BiOBr was proposed to better understand the reaction process. The work provides a facile route for rational design of heterojunction photocatalysts with promising prospect for the treatment of antibiotic residues in various wastewaters.

Ag Loading Enhanced Photocatalytic Activity of g-C3N4 Porous Nanosheets for Decomposition of Organic Pollutants

The g-C3N4 porous nanosheets with different loading amount of Ag nanoparticles (NPs) are successfully prepared by a simple liquid-phase reduction method. These Ag/g-C3N4 composites have an improved photocatalytic performance for decomposing organic pollutants compared with that of pure g-C3N4 nanosheets. Many measurements have been used for characterizing the samples, such as XRD, FTIR, UV-Vis DRS, PL, XPS, EDS, SEM, and TEM. In Ag/g-C3N4, the Ag NPs are uniformly coated on the g-C3N4 surface, the diameter is mainly in the range of 8~18 nanometers. Loading of Ag NPs expand the response to the visible light for g-C3N4 and increasing the producing rate of photogenerated e--h+ pairs. The loading of silver NPs obviously enhances the photocatalytic activity of C3N4 nanosheets toward the Rhodamine B (RhB) decomposition under the simulated sunlight irradiation. With different loading amounts of Ag NPs, Ag/g-C3N4 (3 wt% of Ag) showed the highest photocatalytic activity for RhB decomposition among these as-prepared samples, which is 10 times of the rate of pure C3N4. Based on the experimental results, a possible photocatalytic mechanism for Ag/g-C3N4 is proposed.

Fe3O4 Nanoparticles Grown on Cellulose/GO Hydrogels as Advanced Catalytic Materials for the Heterogeneous Fenton-like Reaction

Cellulose/graphene oxide (GO)/iron oxide (Fe3O4) composites were prepared by coprecipitating iron salts onto cellulose/GO hydrogels in a basic solution. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared, and X-ray diffraction characterization showed that Fe3O4 was successfully coated on GO sheets and cellulose. Cellulose/GO/Fe3O4 composites showed excellent catalytic activity by maintaining almost 98% of the removal of acid orange 7 (AO7) and showed stability over 20 consecutive cycles. This performance is attributable to the synergistic effect of Fe3O4 and GO during the heterogeneous Fenton-like reaction. Especially, the cellulose/GO/Fe3O4 composites preserve their activity by keeping the ratio of Fe3+/Fe2+ at 2 even after 20 catalysis cycles, which is supported by XPS analysis.

Ultrasound assisted dispersion of Bi2Sn2O7-C3N4 nanophotocatalyst over various amount of zeolite Y for enhanced solar-light photocatalytic degradation of tetracycline in aqueous solution

Bi₂Sn₂O₇-C₃N₄/Y nanophotocatalyst with various ratios of zeolite and high activity under simulated solar light irradiation were successfully synthesized using ultrasound-assisted dispersion method. The effect of different amounts of zeolite (10, 20 and 30 wt%) on the photocatalytic degradation of antibiotic tetracycline was investigated. The as-prepared nanophotocatalysts were characterized by XRD, FESEM, EDX, BET, FTIR, DRS and pH_pzc techniques. The degradation results demonstrated that, Bi₂Sn₂O₇-C₃N₄/Y(10) nanophotocatalyst with a degradation efficiency of about 80.4% is an optimum sample. This result can be attributed to the zeolite as a support that prevented the accumulation of Bi₂Sn₂O₇-C₃N₄ active phase and increased access to active sites. Furthermore, it enhanced the adsorption capacity of tetracycline on the photocatalyst surface; that it is beneficial for tetracycline photocatalytic oxidation. Also the results of the DRS analysis indicated that the sharp absorption edge for optimum sample Bi₂Sn₂O₇-C₃N₄/Y at about 480 nm and was active in the visible light range. Eventually, different operational parameters such as photocatalyst loading, concentrations of pollutant and pH solution were investigated. In addition, the degradation mechanism was suggested for TC removal.

Sono-precipitation of Ag2CrO4-C composite enhanced by carbon-based materials (AC, GO, CNT and C3N4) and its activity in photocatalytic degradation of acid orange 7 in water

Enhancing the photocatalytic activity of Ag₂CrO₄ with coupled carbon-based materials like activated carbon, graphene oxide, carbon nanotubes and carbon nitride has been investigated in removal of Acid Orange 7 from wastewater. Sono precipitated Ag₂CrO₄-C composite based photocatalysts were characterized by XRD, BET, FESEM, FTIR and UV-vis DRS and the photocatalytic activity of theses samples was evaluated in terms of degradation amount of acid orange 7 under visible light irradiations. BET analysis showed that with addition of carbon based materials, the specific surface area of the Ag₂CrO₄-C composite increased. XRD analysis indicated that the crystallinity of Ag₂CrO₄ peaks decreased after addition of all studied carbon-based materials and C₃N₄ has lowered the crystallinity of Ag₂CrO₄ less than others. Higher crystallinity has the positive effect of higher photocatalytic activity because among above mentioned composites, Ag₂CrO₄-C₃N₄ photocatalyst exhibited higher photocatalytic activity and stability under visible light irradiations. DRS analysis confirmed good match of electronic structures of Ag₂CrO₄ and C₃N₄. On the other hand Ag₂CrO₄ and C₃N₄ formed heterojunction which separates photo-generated electron-hole pairs effectively. Also evaluation of photocatalytic reaction in various operating parameters showed Ag₂CrO₄-C₃N₄ had the highest photocatalytic activity in neutral pH and 1g/L of catalyst loading.

Sono-coprecipitation synthesis and physicochemical characterization of CdO-ZnO nanophotocatalyst for removal of acid orange 7 from wastewater

In this research, CdO-ZnO nano-photocatalysts were synthesized in various compositions by ultrasound assisted co-precipitation method. The samples were investigated via analyses of XRD, FESEM, BET, DRS, FTIR and EDX dot mapping to determine the physical, chemical and optical properties of the nanocomposites. Successful synthesis of CdO-ZnO photocatalyst in crystalline form was confirmed by XRD analysis resulting lower crystallite sizes for ZnO compared to CdO in the composites. The FESEM analysis demonstrated a nanostructured catalyst with a distinct decrease in particle size by addition of CdO to ZnO photocatalyst. The particle size distribution analysis determined an average particle size of 67.9 for the CdO25ZnO75-SCP sample. According to EDX dot mapping results, the Cd dispersion has been enhanced for the case of sonicated samples. Consequently, these cases have represented higher BET surface area results. Degradation of azo dye from synthetic wastewater was performed in order to evaluate the photocatalytic activity of the samples. The characterization analyses along with the performance tests concluded better properties in the case of ultrasound assisted co-precipitation. The investigation of various compositions resulted the best performance for CdO50ZnO50-SCP nanophotocatalyst reporting 69% of contaminant degradation during 140min of the experiment.

One-pot combustion fabrication of grain-like mesoporous intra-heterostructure BixOyClz nanophotocatalyst with substantial solar-light-driven degradation of antibiotic ofloxacin: influence of various fuels

Photocatalytic degradation of ofloxacin over the intra-heterostructure of grain-like Bi_xO_yCl_z nanophotocatalyst fabricated via one-pot solution combustion synthesis at low temperatures.

Enhanced photocatalytic activity of BiOI under visible light irradiation by the modification of MoS2

The suitable modification of MoS₂ with 3D hierarchical BiOI could improve the separation efficiency of photogenerated charge carriers.