Photodegradation Performance Research Articles

The Wood/MoS2 Composites with Good Adsorption and Photocatalytic Ability for Highly Efficient Removal of Organic Dye Molecules

AbstractOrganic dye‐contained wastewater is a major threat to the global environment and public health. In this study, natural wood and MoS2 are combined to create effective photocatalysts for removing organic pollutants from water under light irradiation. The results show that the photocatalytic degradation activity of wood/MoS2 composites are obviously superior to that of natural wood under solar light as well as possess outstanding stability after three reaction cycles. The improvement in photocatalytic performance for photodegradation is primarily due to an increase in specific surface area and the introduction of catalytic active sites from the edge S, which favors adsorption of organic pollutants and accelerates the degradation process. The synergistic effect of adsorption and photocatalysis also ensures that the composited catalyst is highly universal in its application to organic dye degradation, including RhB (Rhodamine B), MB (Methylene Blue), and MO (Methyl Orange); the kinetic constant for the photocatalytic degradation of RhB, MO, and MB are 0.040, 0.035, and 0.032 min−1, respectively and the degradation performance can be well maintained after three cycle tests. Our study has proved that the wood/MoS2 composite is a novel, low‐cost photocatalyst that plays an important role in environmental protection.

Synthesis and characterization of enhanced visible light-driven C-doped ZnO-2D GO/g-C3N4 heterojunction photocatalyst

Well-designed 2D graphene oxide-modified polymeric graphitic carbon nitride composite nanosheets (GO/g-C3N4) as desirable sensitizers and catalytic substrates for optimising the visible light-driven photocatalytic performance of ZnO-based photocatalysts have been investigated. Herein, 2D GO/g-C3N4 composite nanosheets are first developed by ultrasonic and hydrothermal methods, and then coupled with ZnO nanoparticles to prepare a series of ternary GO/g-C3N4-ZnO heterojunction composites with vary GO loading concentrations. Characterization of the photocatalysts was carried out by SEM, TEM, XPS, XRD, DRS, photoluminescence (PL) spectroscopy; evaluation of the visible light photocatalytic activity was performed by degrading an aqueous methylene blue (MB) solution. XPS studies showed that the formation of a ZnC bond in 15 % GO/g-C3N4-ZnO is due to the replacement of oxygen by carbon, indicating the construction of a hybrid heterojunction composed of C-doped ZnO and visible light sensitive GO/g-C3N4 composite nanosheets. The photodegradation performance of 15 % GO/g-C3N4-ZnO is 5.3, 2.9, and 2.2 times higher than that of pure ZnO, g-C3N4, and g-C3N4-ZnO, respectively. Due to the increase of GO loading in GO/g-C3N4 composite nanosheets, some characteristics of efficient visible light photocatalysis, such as a wider light absorption range, fluorescence quenching in the PL spectrum, excellent optical response in photocurrent measurement, and good stability，were confirmed and can be attributed to the electronic interaction between heterostructures and the effective transfer of photogenerated electrons in these ternary nanocomposites. This work may provide a new promising pathway for the construction of easily prepared 2D GO/g-C3N4 hybrid-modified nanocomposites, which is a hopeful material for wastewater control.

Poly(m-phenylene isophthalamide) (PMIA) membranes as a support for WO3/g-C3N4 for the degradation of diclofenac in water

One of the obstacles hampering large-scale semiconductor photocatalysis is the requirement for the recovery and reuse of photocatalytic nanoparticles. Polymeric membranes are viable and practical support materials for photocatalytic nanoparticles to result in multifunctional photocatalytic membranes. PMIA membranes were applied as support for photocatalytic WO3/g-C3N4 nanoparticles and evaluated for the photodegradation of diclofenac (DFC). The PMIA photocatalytic membranes were prepared using the conventional phase inversion method in which the photocatalyst was embedded into the membranes. SEM, XRD, XPS, and FTIR analysis confirmed the incorporation of WO3/g-C3N4 into PMIA membranes. The contact angle of the PMIA/WGC membranes was reduced from 56.3° for the pure PMIA membrane to 37.5°, and porosity was increased from 74.7 up to 85.3%. The photocatalytic membranes were irradiated in the visible light region. M5, which contains 2% of WO3/g-C3N4 in the PMIA membrane, presented the highest degradation of DFC (85%) after 150 min compared to the other membranes. The degradation performance of DFC using PMIA/WGC was mainly driven by hydroxyl radicals and singlet oxygen. The photodegradation performance within 10 cycles had a difference of less than 5%, indicating the stability of membranes. The PMIA membranes are viable photocatalyst support materials with potential dual functionality in water treatment.

In-situ template etching synthesis of BiON/BiOCl0.9I0.1 heterojunction for photocatalytic degradation of tetracycline

Hierarchical heterostructures have emerged as promising candidates for the efficient photocatalytic degradation of antibiotics owing to their matched energy levels and tunable absorption bands. Herein, we report the facile synthesis of a heterojunction photocatalyst composed of basic bismuth nitrate (BiON) and BiOCl0.9I0.1 using a simple room-temperature hydrolysis method. Our results demonstrate that the BiON/BiOCl0.9I0.1 composite exhibits superior photodegradation performance compared to pure-phase materials owing to the catalytic enhancement at the heterointerface and the effective separation of the photogenerated carriers. Moreover, the unique three-dimensional microsphere morphology of the synthesized composite enhances its specific surface area and light absorption, further enhancing its photocatalytic activity. In the tetracycline (TC) photodegradation reaction as a model reaction, the catalyst could degrade 88% of TC in just 25 min. Overall, this work provides a promising strategy for the facile and low-cost synthesis of heterogeneous photocatalytic degradation materials.

Highly efficient Z-scheme Ag3PO4/PtNPs/g-C3N4 photocatalyst for degradation of organic pollutants in water

Organic pollutants in water cause serious waste of water resources. Therefore, it is important to design efficient photocatalysts to address the problem of waste water. Herein, solid Z-scheme heterojunction photocatalyst, Ag3PO4/PtNPs/g-C3N4, was prepared via in-situ deposition. Under xenon lamp (full wavelength) irradiation, the catalyst efficiently degraded solutions of rhodamine B and phenol within 9 min and 30 min, respectively. This shows better photodegradation performance (99.4% of Rh B, and 97.0% of phenol) than other catalysts and demonstrates that the synergistic effect of its three components results in improved photocatalytic activity. Furthermore, holes and superoxide radicals were identified as main active species during catalysis with Ag3PO4/PtNPs/g-C3N4 based on scavenging experiments of active species and electron spin resonance detection results. In proposed photocatalytic mechanism, PtNPs act as a bridge and accelerate charge transfer on ternary Ag3PO4/PtNPs/g-C3N4. This study provides ternary Z-scheme heterojunction photocatalyst construction for application in the treatment of organic pollutants.

A novel 3D solar evaporator constructed based on the principle of interface evaporation and its application in oil removal and environmental control

It is a challenge to construct devices for producing clean and purified water. In this paper, devices assembled using an aerogel-hydrogel composite and a floating layer were used to produce clean water while purifying water sources. A low-surface-tension polymer and bismuth molybdate were loaded to the surface of a carrier through co-deposition. The contact angle of the constructed superhydrophobic fabric, canvas and felt was 162°, 159° and 160° respectively. Even under the external force of deformation, the beads still quickly left the surface, showing a low adhesion effect. The purification efficiency of the assembled self-floating solar steam generator was 99.82 % and 99.48 % for rhodamine B (Rh B) and methyl orange (MO) respectively, whose mechanical stability and salt suppression capacity were demonstrated through stress–strain curves and photothermal experiments with a high saline concentration (10 wt% NaCl). Through the introduction of bismuth molybdate in the floating layer, not only the roughness increased, but the properties of photodegradation performance were also achieved. Through an active substrate capture test and a band structure analysis, the h+ played a decisive role in the degradation process. The valence and conduction band position of the catalyst were 2.28 eV and −0.35 eV, respectively.

Band structure induced photodegradation mechanism of PEI-based carbon quantum dots for tetracycline and toxicity evaluation for these intermediates

Many kinds of carbon quantum dots (CQDs) are already released into the environment, and the factor that determine the photodegradation ability of these CQDs for antibiotics is still unclear. Herein, three PEI-based CQDs (CAPEI, HAPEI and BCNPEI) were prepared by hydrothermal method to clarify the structural factors that determine their photodegradation performance against tetracycline (TC) when exposed to visible light. Experimentally, BCNPEI photodegraded 62 % of TC, while CAPEI and HAPEI photodegraded TC only about 5–8 %. Sizes, functional groups, aromaticity and energy band structures of these CQDs have been analyzed, and the energy band structure has the best linear relationship with the photodegradation properties of CQDs on TC. The conduction band (CB) value of BCNPEI is − 0.623 V and the valence band (VB) value is 2.207 V, which are strong enough to produce hydroxyl radicals (·OH) and superoxide radicals (·O2-) under visible light exposure. And this has been verified with photoactive species capture experiments and ESR experiments. Thus, band structure is the factor that determine the photocatalytic performance of CQDs for TC. Furthermore, a possible photodegradation pathway of TC by CQD was proposed in a study of high-performance liquid chromatography-mass spectrometry (HPLC-MS) results. The photodegradation intermediates of TC were less toxic than TC, suggesting that the photodegradation of TC by CQD can reduce its environmental risk. In this study, valuable insights are provided into the behavior of CQDs exposed to the environment.

Using waste silver metal in synthesis of Z-scheme Ag@WO3-CeO2 heterojunction to increase photodegradation and electrochemical performances

Design of a Z-scheme heterojunction structure is eco-friendly due to its multi-nanocatalyst performances like wastewater treatment, antibacterial and electrochemical activity. Herein, Ag was extracted from waste batteries in a nitric acid leaching manner. Also, WO3 nanorods and WO3-CeO2 were synthesized by the surfactant-assisted hydrothermal acidic and sol–gel methods, respectively. Silver nanoparticles were doped by wet impregnation method to prepare ternary (Ag@WO3-CeO2) and binary (Ag@WO3 and Ag@CeO2) heterojunctions. The band gap of the prepared Ag@WO3-CeO2 was remarkably diminished in comparison with the rest of the sample (from 2.73 to 2.59 eV). The Langmuir-Hinslewood model showed that ternary systems can degrade methylene blue twice as much as WO3-CeO2 and seven times more than single-component systems. This was due to the presence of silver as a mediator for the transfer of photogenerated electrons between two semiconductors. Also, methylene blue was degraded by more than 90.8% efficiency. Electrochemical impedance spectroscopy (EIS) analysis confirmed that the charge transfer resistance of Ag@WO3-CeO2 was decreased by more than 50%. The results of bactericidal activeness confirmed elevated inhibition capability of Ag@WO3-CeO2 towards E.coli with 99% degradation. X-ray fluorescence (XRF) results confirmed that 98% of silver can be re-extracted after 5 photocatalytic uses which is a material with green technology.

S-scheme heterojunction of hollow corncob-like ZnIn2S4/LaFeO3 for water splitting and tetracycline degradation

Reasonable design of heterojunction photocatalysts with high-quality interfacial coupling is an effective way to improve the photocatalytic activity of semiconductors. Herein, we successfully decorated Zinc indium sulfide (ZnIn2S4, ZIS) on perovskite Lanthanum ferrite (LaFeO3, LFO) with more active sites by a pre-hydrothermal combined post-calcination method, and constructed S-scheme heterojunction photocatalyst with a unique hollow corncob-like morphology for efficient photocatalytic hydrogen production and tetracycline (TC) degradation. When the mass ratio of LFO is 35% and 15%, the ZIS/LFO photocatalyst exhibits the best hydrogen evolution rate and TC photodegradation performance, respectively. Notably, the optimum hydrogen production rate is 6 times that of pure ZIS with excellent cycling stability. The enhanced photoactivity can be explained by the hollow corncob-like morphology and the formed S-scheme heterojunction with close interface contact between ZIS and LFO, which significantly improves the spatial separation and migration efficiency of photoexcited carriers, while maintaining a high redox potential. Finally, it provides an effective support for the photocatalytic mechanism through calculation results of density functional theory. This work not only provides a novel construction strategy of photocatalysts for efficient photocatalytic hydrogen evolution and organic pollutant degradation, but also opens up a new insight for perovskite-modified S-scheme heterojunction.

Structure phase-dependent dielectric and photodegradation properties of Co-doped TiO2 nanoparticles synthesized via co-precipitation route

This research pursued the effect of various calcination temperatures (300–1000 °C) on developing structural phases and the optical, dielectric, and photodegradation characteristics of cobalt-doped titanium dioxide nanoparticles (TiO2 NPs). The prepared NPs were characterized using X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared (FTIR) spectroscopy analysis, ultraviolet–visible light (UV–VIS) spectroscopy, and photodegradation of methylene blue in the presence of visible light. XRD analysis revealed the formation of a tetragonal anatase phase for the samples calcined at 300–600 °C, while the Co-doped samples calcined at 800 °C and 1000 °C displayed a tetragonal rutile phase. The optical band gap analysis indicated that doping in the host matrix produced lower band gap energy for all the prepared samples. Dielectric measurements showed that the rutile phase heated at 800 °C had a larger dielectric constant and dielectric loss than the un-doped TiO2 and the other cobalt-doped samples. Finally, the anatase Co-doped TiO2 exhibited a maximum MB degradation of 93 % in 90 min compared to un-doped TiO2, which only degraded 14 % and rutile-TiO2 NPs (62 % degradation). The underlying mechanism responsible for the diverse photodegradation performance displayed by the anatase and rutile phases of TiO2 NPs is discussed. Overall, these results demonstrate that cobalt doping and the crystalline phase of TiO2 NPs are vital parameters involved in optimizing the photocatalytic activity of TiO2.

Recent Advances in MXenes Based Composites as Photocatalysts: Synthesis, Properties and Photocatalytic Removal of Organic Contaminants from Wastewater

AbstractMXene has indeed gained significant attention in recent years as a promising photocatalyst for various applications, including photocatalytic degradation of pollutants. MXene possesses several unique physical and chemical properties that make it suitable for such applications, including its uniform planar structure, strong metal conductivity, effective functional groups, and numerous derivatives. These properties contribute to the excellent photodegradation performance and long‐term stability exhibited by MXene‐based photocatalysts compared to other photocatalysts. MXene‐based composites, which are formed by incorporating MXene with other materials, demonstrate even better photodegradation activity due to their abundant active sites and porous structure. One crucial factor influencing the photodegradation performance of MXene‐based photocatalysts is the presence of active functional groups on the surface of MXene. These functional groups play a significant role in the photocatalytic process and contribute to the overall efficiency of the catalyst. To provide a broader understanding of MXene‐based photocatalysts, the physicochemical properties of MXene are briefly described in this review. This includes its structural characteristics, electrical conductivity, and the presence of functional groups. This review also investigates the physical and chemical synthesis routes for preparing MXene, both in its natural state and as composites with other materials. These synthesis methods are essential for tailoring the properties of MXene‐based photocatalysts to meet specific requirements. Finally, the review discusses future work and challenges in MXene‐based photocatalysis. This field holds great promise for addressing environmental concerns and improving the degradation of organic compounds. However, further research is needed to optimize the synthesis methods, enhance the photocatalytic efficiency, and explore the practical applications of MXene‐based photocatalysts.

Erythritol assisted facile green synthesis of bismuth-rich photocatalyst Bi7O9I3 with enhanced photocatalytic degradation performance

In this work, Bi7O9I3 with efficient photodegradation performance was facilely and greenly synthesized by the synergistic effect of erythritol and sodium hydroxide at room temperature and atmospheric pressure, where erythritol was first used to produce bismuth-rich photocatalysts. This novel synthetic route has several outstanding features such as green chemistry, high yield, mild conditions, high efficiency, use of simple equipment and inexpensive raw materials. The structural, morphological, optical and photoelectrochemical properties of as-synthesized samples were investigated by XRD, XPS, FT-IR, TEM, UV–vis DRS, BET, PL, EIS and PC analysis. The optimal Bi7O9I3-0.1 photocatalyst achieved 97.6% degradation efficiency of 20 mg/L bisphenol A (BPA) at pH 6.5 with catalyst dosage of 0.34 g/L within 60 min under simulated sunlight irradiation, which 2.09 times higher than that of Bi7O9I3 prepared by the conventional hydrothermal route. Bi7O9I3-0.1 also exhibited higher photodegradation efficiency for a variety of organic pollutants such as tetracycline (TC, 93.1%), ciprofloxacin (CIP, 76.8%), phenol (73.2%), rhodamine B (RhB, 96.2%) and methylene blue (MB, 94.2%). The primary oxidative species inducing BPA degradation were •O2– and h+ determined by scavenger and EPR tests, and the carriers transfer mechanism in Bi7O9I3 was postulated. The photodegradation pathway of BPA was proposed on the basis of LC/MS analysis. The biological toxicity of degradation intermediates was reduced compared to that of BPA according to ECOSAR analysis. Reusability runs demonstrated the chemical and structural stability of the synthesized Bi7O9I3. This work provided a simple route to synthesize bismuth-rich photocatalysts for the degradation of environmental pollutants.

Synergistically Enhanced Photocatalytic Degradation by Coupling Slow-Photon Effect with Z-Scheme Charge Transfer in CdS QDs/IO-TiO2 Heterojunction.

Lower light absorption and faster carrier recombination are significant challenges in photocatalysis. This study introduces a novel approach to address these challenges by anchoring cadmium sulfide quantum dots (CdS QDs) on inverse opal (IO)-TiO2, which increases light absorption and promotes carriers' separation by coupling slow-photon effect with Z-scheme charge transfer. Specifically, the IO-TiO2 was created by etching a polystyrene opal template, which resulted in a periodic structure that enhances light absorption by reflecting light in the stop band. The size of CdS quantum dots (QDs) was regulated to achieve appropriate alignment of energy bands between CdS QDs and IO-TiO2, promoting carrier transfer through alterations in charge transfer modes and resulting in synergistic-amplified photocatalysis. Theoretical simulations and electrochemical investigations demonstrated the coexistence of slow-photon effects and Z-scheme transfer. The system's photodegradation performance was tested using rhodamine B as a model. This novel hierarchical structure of the Z-scheme heterojunction exhibits degradability 7.82 and 4.34 times greater than pristine CdS QDs and IO-TiO2, respectively. This study serves as a source of inspiration for enhancing the photocatalytic capabilities of IO-TiO2 and broadening its scope of potential applications.

Gram-scale synthesis of atomically dispersed p-block Al atoms on polymeric carbon nitride for efficient antibiotic photodegradation

Single-atom decorating polymeric carbon nitride (PCN) is often regarded as a class of promising catalyst for energy conversion and environmental remediation due to its ultrahigh atom utilization and unparalleled performance. Herein, gram-scale atomically dispersed p-block aluminum (Al) atoms on PCN photocatalyst (denoted as ACN) was successfully synthesized via a facile thermal polymerization strategy. Atomic-level, optical characterizations and band structure analysis unveil that Al atoms are uniformly dispersed on PCN framework, which can effectively optimize the band structure, accelerate the separation and transport ability of carriers, and then facilitate antibiotics photodegradation efficiency. Remarkably, the optimal ACN-2 exhibits superb removal rates (∼80%) and outstanding pseudo-first-order kinetic constants (0.084 min−1, 0.051 min−1 and 0.067 min−1, respectively) over visible-light-induced degradation of tetracycline, oxytetracycline and chlortetracycline in just 20 min, and ca. 95% of the original removal rate can be maintained even in 10 consecutive TC degradation cycles, illustrating the superior stability and reusability of ACN-2. Notably, >30 g of photocatalyst (i.e., ACN-500) obtained via precursor amplification procedure still displayed excellent TC photodegradation performance. This work paves the way for practical application of an advanced single-atom Al-decorated PCN photocatalyst for pollutant remediation.

Construction of TiO2/BiOCl S-Scheme heterojunction and photocatalytic degradation of norfloxacin

TiO2/BiOCl heterojunction photocatalysts with different Ti/Bi weight ratios were synthesized by hydrothermal method and used for the photodegradation of norfloxacin (NOF). The as-prepared photocatalysts were characterized. The influences of temperature, catalyst dosage, initial NOF concentration and pH on the photodegradation performance were examined. Based on the results of HPLC-MS, intermediates and possible degradation pathways for NOF degradation were proposed. Based on TOC and 3D EEMs analysis, the mineralization ability of TiO2/BiOCl composites on NOF molecules was investigated. Finally, the possible mechanism for the enhancement of photocatalytic activity of TiO2/BiOCl photocatalyst was presented based on the density functional theory (DFT) calculations, experimental results of radical trapping and analysis of the charge transfer scheme under the internal electric field (IEF) formed in the heterostructure.

The performance and mechanism for photocatalytic degradation of methylene blue catalyzed by ultrathin NiAl-layered double hydroxides

Ultrathin materials are widely used in various photocatalytic reactions due to their large specific surface area, multi-surface active sites, easy carrier separation and transport. In this work, ultrathin NiAl-layered double hydroxides (U-LDHs) nanosheets were prepared by a urea-assisted strategy for photocatalytic degradation of methylene blue. Atomic force microscopy (AFM) measurements show that the thickness of U-LDHs nanosheet is generally between 3 and 8 nm, with a wide pore size distribution and a high specific surface area (109 m2/g). U-LDHs nanosheets can remove 92.42% of methylene blue after 90 min light irradiation, which is nearly 40% higher than that of bulk NiAl-LDHs (B-LDHs). In addition, combined with photoelectric performance characterization and density functional theory calculation, it is confirmed that the U-LDHs nanosheets are much better to the separation and transfer of photogenerated carriers compared with the bulk LDHs. Besides, U-LDHs is conducive to adsorb oxygen to generate superoxide radicals, promoting the progress of photocatalytic reactions and significantly improving photodegradation performance.

Boosting VOCs photodegradation performance of Co-doped WO3 nanofibers through efficient oxygen activation and localized electric field construction

Exploring efficient photocatalysts for degrading hazardous volatile organic compounds (VOCs) is gaining increasing popularity. Herein, we developed Co-doped WO3 nanofibrous photocatalysts by incorporating Co dopant into the WO3 lattice, where hexavalent W(VI) is replaced with divalent Co(II). This heterovalent substitution causes significant charge rearrangement around the Co dopant, resulting in a localized electric field (LEF) that enhances oxygen adsorption and activation. Such an electric field drives photoexcited electrons to gather at the Co dopant, thereby achieving spatial charge separation. Both the efficient oxygen activation and LEF forming contribute to the production of superoxide radicals. The Co0.8-WO3 nanofibers demonstrated improved photocatalytic oxidation of gaseous HCHO and CH3COCH3 compared to WO3. This study highlights the significant promotion of dopant-induced oxygen adsorption and LEF-induced efficient carrier separation. These findings offer a new direction for developing more efficient photocatalysts using unique doping approaches.

The study on the use of a biocatalyst based on Calcined Cow Teeth-TiO2 composite in degrading the methylene blue dye

Cow teeth are a type of natural biomaterial exhibiting a unique hierarchical porous structure that has not been widely studied in catalysis. In this work, from a simple deposition and calcination process, a Cow Teeth composite CCT-TiO2 was fabricated using Calcined Cow Teeth as a template and employed as a biocatalyst to remove a specific target dye from an aqueous solution under UV irradiation.The composite, CCT-TiO2, with a dosage of (0.2 g/L), at room temperature and a 3 h treatment time under UV light, showed a positive behavior towards the photochemical degradation of Methylene Blue (C = 0.01 g/L) mainly in a basic medium pH = 8 giving a catalytic efficiency rate up to 98%.The main parameters affecting the efficiency of the photocatalytic treatment, such as pH, the mass of catalyst added to the solution, the percentage of TiO2 in the composite, the concentration of MB at the beginning, the presence of ethanol, the addition of hydrogen peroxide and the temperature were studied to evaluate their influence on the degradation of methylene blue.The photodegradation performance is inversely proportional to the initial dye concentration. Similarly, for the temperature, the higher the temperature, the higher the photodegradation performance (removal rate 57% for a temperature of 55 °C). However, the presence of ethanol in the solution has a negative impact on the oxidation process, with a yield of 56% after 4 h30 min of treatment under UV irradiation. On the other side, the addition of oxygenated water considerably improves the photodegradation performances of methylene blue, with an efficiency of dye removal going up to 87% after 1 h of treatment.The excellent catalytic degradation performance and low cost suggest that this process has significant potential for effectively treating industrial wastewater loaded with cationic dye.

Facile assembly of CoS/Ag2MoO4 nanohybrids for visible light-promoted Z-type-induced synergistically improved photocatalytic degradation of antibiotics

Antibiotics have distinguished as hazardous emerging pollutants in environment, since they do not fully decomposed. Semiconductor photocatalysis are a promising technology for degradation of refractory organic pollutants under visible illumination. The assembly of compatible photocatalytic heterojunctions with suitable band structures achieves a promising approach for boosting the photodegradation performance. Herein, novel heterogeneous structured CoS/Ag2MoO4 nanohybrids were simply constructed via precipitation and tested by range of characterization procedures (XRD, UV–vis DRS, FESEM, TEM, PL, EIS, N2-adsorption/desorption, and EDX). At a specific conditions (photocatalyst dose 0.3 g/L, pH natural, and levofloxacin (LFX) antibiotic concentration 20 ppm), the CoS/Ag2MoO4 nanohybrid presented LFX degradation performance of 98.6 % in 90 min of solar-simulated illumination, which is exceeding that of pristine Ag2MoO4 (42%) and bare CoS (27%). The mechanism together with the photodegradation pathways were clarified in details. It is demonstrated that the extended range of visible light absorption and improved charge carriers separation induced by the plasmonic Z-type heterojunction formed between Ag2MoO4 and CoS were in charge for the enhancement of photocatalytic efficiency. The present work can contribute to develop effective and rapid photocatalysts for environmental requirements.

Synergistic Promotion of Photocatalytic Degradation of Methyl Orange by Fluorine- and Silicon-Doped TiO2/AC Composite Material.

The direct or indirect discharge of organic pollutants causes serious environmental problems and endangers human health. The high electron-hole recombination rate greatly limits the catalytic efficiency of traditional TiO2-based catalysts. Therefore, starting from low-cost activated carbon (AC), a photocatalyst (F-Si-TiO2/AC) comprising fluorine (F)- and silicon (Si)-doped TiO2 loaded on AC has been developed. F-Si-TiO2/AC has a porous structure. TiO2 nanoparticles were uniformly fixed on the surface or pores of AC, producing many catalytic sites. The band gap of F-Si-TiO2/AC is only 2.7 eV. In addition, F-Si-TiO2/AC exhibits an excellent adsorption capacity toward methyl orange (MO) (57%) in the dark after 60 min. Under the optimal preparation conditions, F-Si-TiO2/AC showed a significant photodegradation performance toward MO, reaching 97.7% after irradiation with visible light for 70 min. Even under the action of different anions and cations, its degradation efficiency is the lowest, at 64.0%, which has good prospects for practical application. At the same time, F-Si-TiO2/AC has long-term, stable, practical application potential and can be easily recovered from the solution. Therefore, this work provides new insights for the fabrication of low-cost, porous, activated, carbon-based photocatalysts, which can be used as high-performance photocatalysts for the degradation of organic pollutants.