An efficient and magnetically recoverable g-C3N4/ZnS/CoFe2O4 nanocomposite for sustainable photodegradation of organic dye under UV-visible light illumination

Sustainable photoelectrocatalytic oxidation of antibiotics using Ag-CoFe2O4@TiO2 heteronanostructures for eco-friendly wastewater remediation

Developing high-performance and durable catalysts presents a significant challenge for oxidizing toxic inorganic and pharmaceutical compounds in wastewater. Recently, there has been a surge in the development of new heterogeneous catalysts for degrading pharmaceutical compounds, driven by advancements in electrocatalysts and photoelectrocatalysts. In this study, a plasmonic Ag nanoparticles decorated CoFe2O4@TiO2 heteronanostructures have been successfully designed to fabricate a high-performing photoelectrode for the oxidation of pharmaceutical compounds. The developed Ag-CoFe2O4@TiO2 possessed a higher electrochemical stability and effectively harvested the UV to visible and NIR radiation in sunlight which generates the enormous photochemical reactive species that involved in the oxidation of ibuprofen in wastewater. Under direct sunlight irradiation, Ag-CoFe2O4@TiO2 achieved complete oxidation of ibuprofen in wastewater at 0.8 V vs RHE. This indicates that metallic Ag nanoparticles are involved in the charge separation and transport of charge carriers from the photoactive sites of CoFe2O4@TiO2, promoting the generation of abundant hydroxy, oxy, and superoxide radicals that actively break the bonds of ibuprofen. Additionally, oxidation agents such as urea and H2O2 were utilized to enhance the formation of superoxide ions and hydroxyl radicals, which rapidly participate in the oxidation of ibuprofen. Significantly, testing for recyclability confirmed the stability of the Ag-CoFe2O4@TiO2 photoanode, ensuring its suitability for prolonged use in photoelectrochemical advanced oxidation processes. Integrating Ag-CoFe2O4@TiO2 photoanodes into water purification systems could enhance economic feasibility, reduce energy consumption, and improve efficiency.

Engineering 0D/2D design of zinc sulfide quantum dots encapsulated with yttrium tungstate nanosheets for improving decomposition of organic dyes and doxycycline hydrochloride drug

Herein, it is demonstrated that 0D/2D design of zinc sulfide quantum dots encapsulated with yttrium tungstate nanosheets, which were subsequently used to increase the removal of brilliant blue (BB), methyl red (MR) dyes and doxycycline drug using UV-visible light. The produced ZnS-Y2WO6 nanohybrids exhibited excellent catalytic activity, reaching degradation efficiencies of around 89.92%, 80% and 85.51 % for BB, MR dyes and doxycycline drug, respectively, with a minimum irradiation duration of 120, 60 and 125 min. These nanohybrids outperformed Y2WO6 in terms of photocatalytic efficacy due to enhanced light absorption, efficient charge transfer, and decreased charge carrier recombination between ZnS and Y2WO6 nanoparticles. The synergistic combination of ZnS and Y2WO6 nanoparticles resulted in multiple active sites on the composite surface. Furthermore, the ZnS-Y2WO6 nanohybrids maintained excellent degradation efficiencies of 79.45% and 70.12% for BB and MR dyes, respectively, even after five consecutive cycles, with no significant loss of catalytic activity. The produced ZnS-Y2WO6 nanohybrids were thoroughly analyzed utilizing a variety of analytical methods. Furthermore, the degradation of organic dyes and doxycycline drug related possible mechanism were examined using experimental data, indicating the potential of ZnS-Y2WO6 nanohybrids as excellent photocatalytic materials for oxidizing organic dyes and drugs in aquatic conditions.

Comprehensive removal of various dyes by thiourea modified chitosan/nano ZnS composite via enhanced photocatalysis: Performance and mechanism

Dyeing wastewater is a carcinogenic pollutant, which is widely known for its harmful effects on humans and marine organisms. In this study, a novel composite was prepared by blending thiourea modified chitosan with zinc sulfide nanoparticles (T-CS/ZnS) to comprehensively remove methyl orange (MO), rhodamine B (Rh B), and methylene blue (MB) effectively. Characterization results suggested that the synthesized composite has an irregular and rough surface that provided high specific surface area for adsorption process, while the strong optical response and low bandgap width contributed to the subsequent photocatalytic degradation of adsorbed dye molecules. Under optimum experimental conditions, the removal rates of MO, Rh B, and MB were 99.59 %, 99.49 %, and 91.04 %, respectively. Amino and hydroxyl groups provide electrons in photocatalytic reactions. The reaction process is consistent with the quasi-first-order kinetic model, and the material has good stability and regeneration potential. This study indicated that T-CS/ZnS composite is a highly effective material for the treatment of dyeing wastewaters.

Designing the heterostructured FeWO4/FeS2 nanocomposites for an enhanced photocatalytic organic dye degradation

The present study, reports a facile approach for the synthesis of FeWO₄/FeS₂ nanocomposites were demonstrated through hydrothermal method. The surface morphology, crystalline structure, chemical composition, optical properties of the prepared samples was analysed by different various technique. The result observed analysis indicates that, the formation of heterojunction by 2:1 wt.% of FeWO₄/FeS₂ nanohybrid has the lowest recombination rate of electron-hole pairs and the least electron transfer resistance. Due to its the broad absorption spectral range and preferable energy band gap, the (2:1) FeWO₄/FeS₂ nanohybrid photocatalyst exhibits an excellent ability to remove MB dye when exposed to UV-Vis. Light irradiation. Its photocatalytic activity of (2:1) FeWO₄/FeS₂ nanohybrid is higher than other as prepared samples due to its synergistic effects, enhanced light absorption and high charge carrier separation. Radical trapping experimental result implies that the photo-generated free electrons and hydroxyl radials are essential to degrade the MB dye. Furthermore, a possible future mechanism for FeWO₄/FeS₂ nanocomposites photocatalytic activity was discussed. Moreover, the recyclability analysis demonstrated that the FeWO₄/FeS₂ nanocomposites can be recycled multiple times. The enhanced photocatalytic activity of 2:1 FeWO₄/FeS₂ nanocomposites is promising for the further application of visible light driven photocatalyst in wastewater treatment.

The Collision between g-C3 N4 and QDs in the Fields of Energy and Environment: Synergistic Effects for Efficient Photocatalysis

Recently, graphitic carbon nitride (g-C₃ N₄ ) has attracted increasing interest due to its visible light absorption, suitable energy band structure, and excellent stability. However, low specific surface area, finite visible light response range (<460 nm), and rapid photogenerated electron-hole (e^- -h⁺ ) pairs recombination of the pristine g-C₃ N₄ limit its practical applications. The small size of quantum dots (QDs) endows the properties of abundant active sites, wide absorption spectrum, and adjustable bandgap, but inevitable aggregation. Studies have confirmed that the integration of g-C₃ N₄ and QDs not only overcomes these limitations of individual component, but also successfully inherits each advantage. Encouraged by these advantages, the synthetic strategies and the fundamental of QDs/g-C₃ N₄ composites are briefly elaborated in this review. Particularly, the synergistic effects of QDs/g-C₃ N₄ composites are analyzed comprehensively, including the enhancement of the photocatalytic performance and the avoidance of aggregation. Then, the photocatalytic applications of QDs/g-C₃ N₄ composites in the fields of environment and energy are described and further combined with DFT calculation to further reveal the reaction mechanisms. Moreover, the stability and reusability of QDs/g-C₃ N₄ composites are analyzed. Finally, the future development of these composites and the solution of existing problems are prospected.

Synergistic Effects of Magnetic Z-Scheme g-C3N4/CoFe2O4 Nanofibres with Controllable Morphology on Photocatalytic Activity

The rational design of interfacial contacts plays a decisive role in improving interfacial carrier transfer and separation in heterojunction photocatalysts. In Z-scheme photocatalysts, the recombination of photogenerated electron-hole pairs is prevented so that the redox capacity is maintained. Here, one-dimensional graphitic carbon nitride (g-C₃N₄)/CoFe₂O₄ fibres were synthesised as a new type of magnetic Z-scheme visible-light photocatalyst. Compared with pure g-C₃N₄ and CoFe₂O₄, the prepared composite photocatalysts showed considerably improved performance for the photooxidative degradation of tetracycline and methylene blue. In particular, the photodegradation efficiency of the g-C₃N₄/CoFe₂O₄ fibres for methylene blue was approximately two and seven times those of g-C₃N₄ and CoFe₂O₄, respectively. The formation mechanism of the Z-scheme heterojunctions in the g-C₃N₄/CoFe₂O₄ fibres was investigated using photocurrent spectroscopy and electrochemical impedance spectroscopy. We proposed that one of the reasons for the improved photodegradation performance is that the charge transport path in one-dimensional materials enables efficient photoelectron and hole transfer. Furthermore, the internal electric field of the prepared Z-scheme photocatalyst enhanced visible-light absorption, which provided a barrier for photoelectron-hole pair recombination.

Tuning the optical properties of high quantum-yield g-C3N4 with the inclusion of ZnS via FRET for high electron-hole recombination

Luminescent polymeric graphitic composites have the potential to be efficient energy converters for sophisticated displays and light sources. Thermal condensation is used to synthesize g-C₃N₄-ZnS composites. The XRD, and FTIR analyses confirmed the synthesis of the pure host, filler, and composites. FESEM, and TEM images revealed that the ZnS nanosheets were evenly distributed over the g-C₃N₄ sheets. As a result of ZnS incorporation, the melting point of g-C₃N₄ has been raised to 748.5 °C, and the thermal stability of gZ has been increased by 27 %. The optimized gZ15 band gap is determined to be 2.98 eV with a crystallite size of 4.2 nm and a micro stain of 35.42 × 10^-3. With a purity of 63.4 %, gZ15 demonstrated a significant rate of recombination in the blue region. gZ15 has a high PLQY of 98 % and a FRET efficiency of 92%. All of the improved properties demonstrated that polymeric g-C₃N₄-ZnS was the optimum materials for usage in the active or emissive layer of optoelectronic devices.

Constructing Z-scheme g-C3N4/TiO2 heterostructure for promoting degradation of the hazardous dye pollutants

The use of dyes and segments has increased widely in recent years, but it poses a serious health risk to ecosystems. In this work, TiO₂ and two-dimensional g-C₃N₄ nanosheets (g-CN) were fabricated through co-precipitation and thermal polymerization technique, respectively. The g-CN-TiO₂ photocatalyst (1: 3, 2: 2, 3: 1) in various weight percentages was prepared using a simple impregnation process. The photocatalytic behaviour of the g-CN, TiO₂ NPs, and different weight percentages of g-CN-TiO₂ photocatalyst was evaluated against methylene blue (MB) dye under UV-visible light illumination. Compared to pristine and other weight percentages of the g-CN-TiO₂ nanocomposite, the optimized g-CN-TiO₂ nanocomposite (3:1) showed promoted performance against MB dye. The enriched catalytic efficiency can be accredited to the low amount of TiO₂ nanoparticles deposited on gCN nanosheets, possibly due to the boosted transport properties of the electron-hole pairs. The enriched photocatalytic behaviour can be attributed to the development of the Z-scheme system between TiO₂ and g-CN. The current study is an outstanding demonstration of the development of maximum catalytic efficiency for destroying hazardous chemical dyes.

Synthesis and characterization of g-C3N4-CoFe2O4-ZnO magnetic nanocomposites for enhancing photocatalytic activity with visible light for degradation of penicillin G antibiotic

Nowadays, antibiotic water pollution is an increasingly dangerous environmental threat. Thus, water treatment is essential for their reduction and removal. In recent decades, photocatalysts have attracted much attention due to their influential role in solving this issue. The photocatalytic process, which is one of the green processes and part of advanced oxidation processes, can be a good choice for treating contaminated water containing non-degradable organic matter. However, the design of high-performance photocatalysts under free sunlight can be challenging. In this study, g-C₃N₄-Ca, Mg codoped CoFe₂O₄-ZnO (gCN-CFO-ZnO) nanocomposite photocatalyst was applied in removing penicillin G (PENG) from drug effluents. Also, the effects of contaminant concentration, initial pH, irradiation time, and zinc oxide ratio in the nanocomposites were investigated. The hydrothermal method was carried out to prepare the appropriate composites. Then, the obtained products were characterized by powder X-Ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), Raman, field-emission scanning and transmission electron microscope (FE-SEM&TEM), energy dispersive X-Ray (EDX), diffuse reflectance spectroscopy (DRS), vibrating sample magnetometer (VSM) and Photoluminescence (PL) techniques. According to the findings, the degradation of PENG in an acidic environment occurred remarkably; under the same conditions, with decreasing pH from 9 to 5 in the gCN-CFO-ZnO (33.33%) nanocomposite, the degradation efficiency grew from 47% to 74%. Also, the degradation rate of PENG in gCN-CFO-ZnO (16.66%) and gCN-CFO-ZnO (50%) nanocomposites under optimal conditions (pH = 5, PENG the concentration of 10 ppm, and irradiation time of 120 min) was achieved 52% and 60%, respectively. Further, gCN-CFO-ZnO (33.33%) nanocomposite showed higher efficiency in PENG degradation compared to the other two nanocomposites.

Solvothermal synthesis of 3D hierarchical Cu2FeSnS4 microspheres for photocatalytic degradation of organic pollutants

In this work, we prepared Cu₂FeSnS₄ (CFTS) microspheres via solvothermal method and studied their photocatalytic performance towards the degradation of organic pollutants. With increasing solvothermal temperature from 160 °C to 180 °C, the morphology of CFTS changes from irregular 2D to hierarchical 3D shapes. Hierarchical 3D CFTS microspheres packed with 2D nanosheets were successfully prepared at 180 °C. During the solvothermal process, octadecyl amine (ODA) acts as a capping agent to prevent the aggregation of particles, while L-cystine functions as an environmentally friendly sulfur source and complexing reagent. The large surface area and mesoporous structure of the as-prepared 3D hierarchical CFTS microspheres provide more active sites, enhance visible light absorption and promote charge separation and transfer, leading to the improved photodegradation performance for RhB and MB compared to the samples prepared at the temperature lower than 180 °C. This work provides a simple and low-cost method for the synthesis of 3D hierarchical CFTS towards photocatalytic applications.