Bioderived Mesoporous Carbon@Tungsten Oxide Nanocomposite as a Drug Carrier Vehicle of Doxorubicin for Potent Cancer Therapy

Scientists have investigated the possibility of employing nanomaterials as drug carriers. These nanomaterials can preserve their content and transport it to the target region in the body. In this investigation, we proposed a simple method for developing distinctive, bioderived nanostructures with mesoporous carbon nanoparticles impregnated with tungsten oxide (WO3). Prior to characterizing and encapsulating WO3 with bioderived mesoporous carbon, the anticancer drug doxorubicin (DOX) was added to the nanoparticles and examined loading and release study. The approaches for both nanoparticle production and characterization are discussed in detail. Colloidal qualities of the nanomaterial can be effectively preserved while also allowing transdermal transportation of nanoparticles into the body by forming them into green, reusable, and porous nanostructures. Although the theories of nanoparticles and bioderived carbon each have been studied separately, the combination presents a new route to applications connected to nanomedicine. Furthermore, this sample was used to study exotic biomedical applications, such as antioxidant, antimicrobial, and anticancer activities. The W-3 sample had lower antioxidant activity (44.01%) than the C@W sample (56.34%), which was the most potent. A high DOX entrapment effectiveness of 97% was eventually achieved by the C@W sample, compared to a pure WO3 entrapment efficiency of 91%. It was observed that the Carbon/WO3 composite (C@W) sample showed more efficacy because the mesoporous carbon composition with WO3 increases the average surface area and surface-active locations.

Photoluminescence and Photocatalytic Properties of MWNTs Decorated with Fe-Doped ZnO Nanoparticles

The present work reports the photoluminescence (PL) and photocatalytic properties of multi-walled carbon nanotubes (MWCNTs) decorated with Fe-doped ZnO nanoparticles. MWCNT:ZnO-Fe nanocomposite samples with weight ratios of 1:3, 1:5 and 1:10 were prepared using a facile synthesis method. The obtained crystalline phases were evidenced by X-ray diffraction (XRD). X-ray Photoelectron spectroscopy (XPS) revealed the presence of both 2+ and 3+ valence states of Fe ions in a ratio of approximately 0.5. The electron paramagnetic resonance EPR spectroscopy sustained the presence of Fe³⁺ ions in the ZnO lattice and evidenced oxygen vacancies. Transmission electron microscopy (TEM) images showed the attachment and distribution of Fe-doped ZnO nanoparticles along the nanotubes with a star-like shape. All of the samples exhibited absorption in the UV region, and the absorption edge was shifted toward a higher wavelength after the addition of MWCNT component. The photoluminescence emission spectra showed peaks in the UV and visible region. Visible emissions are a result of the presence of defects or impurity states in the material. All of the samples showed photocatalytic activity against the Rhodamine B (RhB) synthetic solution under UV irradiation. The best performance was obtained using the MWCNT:ZnO-Fe(1:5) nanocomposite samples, which exhibited a 96% degradation efficiency. The mechanism of photocatalytic activity was explained based on the reactive oxygen species generated by the nanocomposites under UV irradiation in correlation with the structural and optical information obtained in this study.

Research Progress of Tungsten Oxide-Based Catalysts in Photocatalytic Reactions

Photocatalysis technology is a potential solution to solve the problem of environmental pollution and energy shortage, but its wide application is limited by the low efficiency of solar energy conversion. As a non-toxic and inexpensive n-type semiconductor, WO3 can absorb approximately 12% of sunlight which is considered one of the most attractive photocatalytic candidates. However, the narrow light absorption range and the high recombination rate of photogenerated electrons and holes restrict the further development of WO3-based catalysts. Herein, the studies on preparation and modification methods such as doping element, regulating defects and constructing heterojunctions to enlarge the range of excitation light to the visible region and slow down the recombination of carriers on WO3-based catalysts so as to improve their photocatalytic performance are reviewed. The mechanism and application of WO3-based catalysts in the dissociation of water, the degradation of organic pollutants, as well as the hydrogen reduction of N2 and CO2 are emphatically investigated and discussed. It is clear that WO3-based catalysts will play a positive role in the field of future photocatalysis. This paper could also provide guidance for the rational design of other metallic oxide (MOx) catalysts for the increasing conversion efficiency of solar energy.

The synthesis of Pt doped WO3 nanosheets and application on colorimetric detection of cysteine by naked eye using response surface methodology for optimization

We present a simple, sensitive, and specific colorimetric using the peroxidase properties method based on Pt doped WO₃ nanosheets to detect the cysteine. Pt@WO₃NSs were synthesized by hydrothermal method and characterized by Fourier transform infrared (FTIR), Transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction patterns (XRD) methods. The response surface methodology (RSM) method based on the central composite design (CCD) was used to optimize test parameters such as pH, nanosheet concentration, and temperature. When cysteine is present in the environment due to its competition with 3,3', 5,5'-Tetramethylbenzidine (TMB) in the use of hydrogen peroxide, the blue discoloration is reduced compared to the absence of cysteine and leads to its detection. We have favorably created a peculiar approach for sensing cysteine based on the colorimetric method in solution and paper with linear range 0.01-15 μM, 0.005-14 μM and R² = 0.9887 and R² = 0.9871 respectively. The detection limit for solution-based is 1.2 nM and for paper-based is 1 nM.

Theoretical Study of CO Adsorption Interactions with Cr-Doped Tungsten Oxide/Graphene Composites for Gas Sensor Application

The present study explores the CO adsorption properties with graphene, tungsten oxide/graphene composite, and Cr-doped tungsten oxide/graphene composite using density functional theory (DFT) calculations. The results of the study reveal the Cr-doped tungsten oxide/graphene composites, g-CrW n-1O3n (n = 2 to 4), to have a lowered highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap, high surface reactivity, and a strong cluster-graphene binding energy, hence exhibiting a strong adsorption interaction with CO. The CO adsorption interaction shows physisorption properties by having a greater tendency for Mulliken and natural bond orbital (NBO) charge transfer supported by a strong physisorption interaction toward the g-CrW n-1O3n (n = 2 to 4) composite with HOMO-LUMO energy gaps of -0.638, -0.486, and -0.327 eV, respectively. The calculated photoelectron spectroscopy (PES) and infrared spectra combined with the visualized electrostatic potential and contour line confirm the population density of the physisorption interaction. The calculated results show that the g-CrW n-1O3n composite achieves a greater sensing ability by possessing the highest sensitivity, adsorption, and desorption characteristics for n = 2 (g-CrWO6 composite). In conclusion, Cr-doped tungsten oxide/graphene has high sensitivity toward CO gas.

Boosting photoresposive ability of WO3-Bi2O3nanocomposite rods via annealing-induced intrinsic precipitation of nanosized Bi particles

In this study, Bi-particle-functionalized tungsten trioxide-bismuth oxide (WO₃-Bi₂O₃) composite nanorods were prepared by integrating sputtering and hydrothermal syntheses with an appropriate postannealing procedure to induce Bi particle precipitation. Unlike other routes in which metal particle decoration is achieved externally, in this study, photoresponsive one-dimensional WO₃-Bi₂O₃composite nanorods were decorated with Bi particles by using the internal precipitation method. Structural analysis revealed that the Bi-metal-particle-functionalized WO₃-Bi₂O₃composite nanorods with particle size ranging from 5 to 10 nm were formed through hydrogen gas annealing at an optimal annealing temperature of 350 °C. Compared with the pristine WO₃nanorod template, the Bi-WO₃-Bi₂O₃composite nanorods exhibited higher photoresponsive performance, substantial photogenerated charge transfer ability, and efficient separation of photogenerated electron-hole pairs. The study results indicated that the Bi-WO₃-Bi₂O₃composite nanorods had superior decontamination ability and excellent stability toward RhB dye as compared with pristine WO₃. Moreover, the photogenerated charge separation and migration efficiencies of the WO₃-Bi₂O₃nanorods could be tuned through appropriate reduction of the surface oxide layer; this is a promising approach to designing WO₃-Bi₂O₃nanorods with high photoactive performance.

Nickel nanoparticle-decorated reduced graphene oxide/WO3 nanocomposite - a promising candidate for gas sensing

We report for the first time the combination of WO3 sensing elements with a non-noble metal-carbon composite, namely a nickel metal nanoparticle-carbon composite (Ni@rGO). Previous work with WO3 had used either NiO (as part of the WO3 lattice), solely carbon, Pd-surface decorated WO3 (Pd@WO3), or Pd or Pt@carbon@WO3. We demonstrate the gas response for pure WO3, rGO/WO3 and Ni@rGO/WO3 sensing elements towards NO2 and acetone in air as well as towards CO in N2. The addition of 0.35 wt % Ni@rGO composite to WO3 enables the increase of the sensory response by more than 1.6 times for NO2 vapors. The gas response towards acetone using 0.35 wt % Ni@rGO/WO3 composite was 1.5 times greater for 3500 ppm than for 35,000 ppm acetone. For 0.35 wt % Ni@rGO/WO3 composite and CO gas, a response time (T res) of 7 min and a recovery time (T rec) of 2 min was determined.

Challenges and prospects about the graphene role in the design of photoelectrodes for sunlight-driven water splitting

Graphene and its derivatives have emerged as potential materials for several technological applications including sunlight-driven water splitting reactions. This review critically addresses the latest achievements concerning the use of graphene as a player in the design of hybrid-photoelectrodes for photoelectrochemical cells. Insights about the charge carrier dynamics of graphene-based photocatalysts which include metal oxides and non-metal oxide semiconductors are also discussed. The concepts underpinning the continued progress in the field of graphene/photoelectrodes, including different graphene structures, architecture as well as the possible mechanisms for hydrogen and oxygen reactions are also presented. Despite several reports having demonstrated the potential of graphene-based photocatalysts, the achieved performance remains far from the targeted benchmark efficiency for commercial application. This review also highlights the challenges and opportunities related to graphene application in photoelectrochemical cells for future directions in the field.

Engineered two-dimensional nanomaterials: an emerging paradigm for water purification and monitoring

Water scarcity has become an increasingly complex challenge with the growth of the global population, economic expansion, and climate change, highlighting the demand for advanced water treatment technologies that can provide clean water in a scalable, reliable, affordable, and sustainable manner. Recent advancements on 2D nanomaterials (2DM) open a new pathway for addressing the grand challenge of water treatment owing to their unique structures and superior properties. Emerging 2D nanostructures such as graphene, MoS₂, MXene, h-BN, g-C₃N₄, and black phosphorus have demonstrated an unprecedented surface-to-volume ratio, which promises ultralow material use, ultrafast processing time, and ultrahigh treatment efficiency for water cleaning/monitoring. In this review, we provide a state-of-the-art account on engineered 2D nanomaterials and their applications in emerging water technologies, involving separation, adsorption, photocatalysis, and pollutant detection. The fundamental design strategies of 2DM are discussed with emphasis on their physicochemical properties, underlying mechanism and targeted applications in different scenarios. This review concludes with a perspective on the pressing challenges and emerging opportunities in 2DM-enabled wastewater treatment and water-quality monitoring. This review can help to elaborate the structure-processing-property relationship of 2DM, and aims to guide the design of next-generation 2DM systems for the development of selective, multifunctional, programmable, and even intelligent water technologies. The global significance of clean water for future generations sheds new light and much inspiration in this rising field to enhance the efficiency and affordability of water treatment and secure a global water supply in a growing portion of the world.

Progress in Graphene/Metal Oxide Composite Photocatalysts for Degradation of Organic Pollutants

The sewage discharge of industrial wastewater seriously pollutes the water source and rivers, which is very harmful to the health of humans and wildlife. Among those methods for treating wastewater, photocatalysis is a sustainable and environmental-friendly technique for removing the organic pollutants with no secondary pollution. As a popular photocatalyst, graphene/metal oxide nanocomposites have been widely reported in the photocatalysis field. In this review, the recent progress of graphene/metal oxide composites including binary and ternary composites is summarized in detail. The synthesis, microstructure design, and application performance of graphene/TiO2, graphene/ZnO, graphene/SnO2, graphene/WO3, graphene/Fe2O3, and graphene/Cu2O composites are introduced firstly. Then, the synthesis, the selection of components, and the performance of various ternary composites are summarized specifically, including graphene/TiO2-, graphene/ZnO-, graphene/SnO2-, graphene/Cu2O-, graphene/FexOy-, and graphene/Bi-containing ternary composites. At last, the possible research directions of graphene/metal oxide nanocomposites are put forward. The main purpose is to provide a theoretical guidance for designing high-performance graphene/metal oxide photocatalysts for wastewater treatment.

In situ modification of BiVO4 nanosheets on graphene for boosting photocatalytic water oxidation

Owing to the sluggish water oxidation process, unearthing an ideal model for disclosing the impact of an architectural approach on the water oxidation activity of photocatalysts becomes a vital issue. Here, we propose an innovative in situ modification strategy for constructing ultrapure BiVO₄ nanosheets on graphene (u-BVG) toward the accelerated photocatalytic water oxidation reaction. Considering the Mott-Schottky heterojunctions at the contact interface in u-BVG, the feasible electron transfer from excited BiVO₄ to graphene facilitates the holes to migrate onto the BiVO₄ surface for the water oxidation reaction. Compared with the conventional synthesis strategies, our strategy avoids the introduction of Cl impurities. This modification allows for not only a ca. 0.1 eV deeper valence band edge position to generate holes with a stronger oxidation potential but the extraction of the impurity level to suppress the carrier recombination. And density functional theory calculations are in accordance with the above results. Impressively, these merits endow the u-BVG with ca. 16.8 times growth in the amount of ˙OH radicals derived from OH^-/H₂O oxidation, an over 260% enhancement in O₂ yield and a 1.6-fold increase in the apparent quantum efficiency relative to the impure counterpart. This work paves the way for the reconstruction of graphene-based binary systems with high performance in solar-to-chemical energy conversion.

Nitrogen doped carbon quantum dots and GO modified WO3 nanosheets combination as an effective visible photo catalyst

Nitrogen doped carbon quantum dots (NCQDs) based highly efficient ternary photocatalyst are fabricated by modifying surface of GO incorporated WO₃ nano-sheets. XRD confirmed the formation of monoclinicWO₃ nano-sheets. All the characteristic peaks of WO₃, GO and NCQDs are obvious in XRD patterns of WO₃/GO/NCQDs ternary photocatalysts confirming successful fabrication of the photocatalysts. SEM images showed that WO₃ host matrix is distorted after incorporation of GO and NCQDs owing to lower interfacial tension. The surface of WO₃ nano-sheets is modified with morphological defects making more active sites available. UV-vis spectra exhibited extended visible light absorption and remarkable reduction of WO₃ band gap energy. The photoluminescence spectra confirmed the efficient charge separation in NCQDs modified ternary photocatalyst. The synthesized composites were applied for the photocatalytic degradation of harmful organic dye i.e. methyl orange (MO). The ternary composites represented the excellent photocatalytic activity as compared to binary and pure WO₃ photocatalysts. This enhanced photocatalytic activity is attributed to the availability of active sites, extended light absorption in visible region and enhanced charge separation efficiency.

Photocatalytic Oxygen Evolution from Water Splitting

Photocatalytic water splitting has attracted a lot of attention in recent years, and O2 evolution is the decisive step owing to the complex four-electrons reaction process. Though many studies have been conducted, it is necessary to systematically summarize and introduce the research on photocatalytic O2 evolution, and thus a systematic review is needed. First, the corresponding principles about O2 evolution and some urgently encountered issues based on the fundamentals of photocatalytic water splitting are introduced. Then, several types of classical water oxidation photocatalysts, including TiO2, BiVO4, WO3, α-Fe2O3, and some newly developed ones, such as Sillén-Aurivillius perovskites, porphyrins, metal-organic frameworks, etc., are highlighted in detail, in terms of their crystal structures, synthetic approaches, and morphologies. Third, diverse strategies for O2 evolution activity improvement via enhancing photoabsorption and charge separation are presented, including the cocatalysts loading, heterojunction construction, doping and vacancy formation, and other strategies. Finally, the key challenges and future prospects with regard to photocatalytic O2 evolution are proposed. The purpose of this review is to provide a timely summary and guideline for the future research works for O2 evolution.

A study on the synchronous decoration of molybdenum oxide or tungsten oxide nanoparticles on anode materials for natural gas fed solid oxide fuel cells using ultrasounds

Sonochemistry was used for the metal oxides nanoparticle synthesis. All experiments were run using a BANDELIN Sonopuls HD 3200 ultrasonic generator (20 kHz, 200 W net output) with a ultrasonic probe in thermostated environment of 80 °C under ambient air. At the same time, ultrasonication activity achieved their decoration on state-of-the-art fuel cell anode powders. These modified powders shall be used in solid oxide and ceramic proton exchange membrane fuel cells anode sites. Metal oxide nanoformations synthesized were those of tungsten and molybdenum. In case of sonochemical synthesis, organometallic compounds dissolved in organic solvents played the role of precursors. Experiments of metal oxides synthesis revealed that ultrasonication intensity and solvents are able to affect final nanoparticles size distribution and morphology. At the same time, ratio of precursor and substrate compounds amounts as well as ultrasonication intensity and duration were all found to affect the decoration loading extent of nanoformations on substrates. Transmission electron microscopy was mainly used for identifying the final product of each synthesis attempt. Moreover, selected area diffraction of characteristic formations examined, gave important information about the nanocrystallinity and stoichiometry of all materials synthesized.

Synthesis of Graphene Oxide Interspersed in Hexagonal WO3 Nanorods for High-Efficiency Visible-Light Driven Photocatalysis and NH3 Gas Sensing

WO₃ nanorods and GO (at 1 wt% loading) doped WO₃ were synthesized using a template free deposition-hydrothermal route and thoroughly characterized by various techniques including XRD, FTIR, Raman, TEM-SAED, PL, UV-Vis, XPS, and N₂ adsorption. The nano-materials performance was investigated toward photocatalytic degradation of methylene blue dye (20 ppm) under visible light illumination (160 W, λ> 420) and gas sensing ability for ammonia gas (10–100 ppm) at 200°C. HRTEM investigation of the 1%GO.WO₃ composite revealed WO₃ nanorods of a major d-spacing value of 0.16 nm indexed to the crystal plane (221). That relevant plane was absent in pure WO₃ establishing the intercalation with GO. The MB degradation activity was considerably enhanced over the 1%GO.WO₃ catalyst with a rate constant of 0.0154 min⁻¹ exceeding that of WO₃ by 15 times. The reaction mechanism was justified dependent on electrons, holes and •OH reactive species as determined via scavenger examination tests and characterization techniques. The drop in both band gap (2.49 eV) and PL intensity was the main reason responsible for enhancing the photo-degradation activity of the 1%GO.WO₃ catalyst. The later catalyst initiated the two electron O₂ reduction forming H₂O₂, that contributed in the photoactivity improvement via forming •OH moieties. The hexagonal structure of 1%GO.WO₃ showed a better gas sensing performance for ammonia gas at 100 ppm (R_a-R_g/R_g = 17.6) exceeding that of pure WO₃ nanorods (1.27). The superiority of the gas-sensing property of the 1%GO.WO₃ catalyst was mainly ascribed to the high dispersity of GO onto WO₃ surfaces by which different carbon species served as mediators to hinder the recombination rate of photo-generated electron-hole pairs and therefore facilitated the electron transition. The dominancy of the lattice plane (221) in 1%GO.WO₃ formed between GO and WO₃ improved the electron transport in the gas-sensing process.

WO3/p-Type-GR Layered Materials for Promoted Photocatalytic Antibiotic Degradation and Device for Mechanism Insight

Graphene enhanced WO₃ has recently become a promising material for various applications. The understanding of the transfer of charge carriers during the photocatalytic processes remains unclear because of their complexity. In this study, the characteristics of the deposited WO₃/graphene layered materials were investigated by Raman spectroscopy, UV-vis spectroscopy, and SEM. According to the results, p-graphene exhibits and enhances the characteristics of the WO₃/graphene film. The photocatalytic activities of WO₃/graphene layered materials were assessed by the photocatalytic degradation of oxytetracycline antibiotics as irradiated by UV light. Here, a higher current of cyclic voltammetry and a higher resistance of impedance spectra were obtained with the as-grown WO₃/graphene directly synthesized on Cu foils under UV light using an electrochemical method, which was different from traditional WO₃ catalysts. Thus, it is urgent to explore the underlying mechanism in depth. In this study, a large layered material WO₃/graphene was fabricated on a Si substrate using a modified CVD method, and a WO₃/graphene device was developed by depositing a gold electrode material and compared with a WO₃ device. Due to photo-induced doping effects, the current-voltage test suggested that the photo-resistance is larger than dark-resistance, and the photo-current is less than the dark current based on WO₃/graphene layered materials, which are significantly different from the characteristics of the WO₃ layered material. A new pathway was developed here to analyze the transfer properties of carriers in the photocatalytic process.

Regulating effect of heterojunctions on electrocatalytic oxidation of methanol for Pt/WO3-NaTaO3 catalysts

Pt/WO₃-NaTaO₃ composite catalysts for different W/Ta molar ratios were obtained via a facile hydrothermal method.

A review on novel composites of MWCNTs mediated semiconducting materials as photocatalysts in water treatment

Many technologies were explored to eliminate the harmful pollutants entering water systems and to minimize their impact on environment. In general, photo-catalysis is one of the sustainable techniques with wider applications and semiconductors in particular were efficiently utilized in the photocatalytic degradation of pollutants. Semiconducting materials, such as TiO₂, ZnO, BiO, CdS, and Ag₃PO₄ are frequently used as photo-catalysts due to their suggestible band gap and structural properties. The generation of reactive oxygen species such as hydroxyl and superoxide radicals is the crucial factor in degradation of pollutant molecules. The rapid recombination of photo-generated electron-hole pairs impacts on the efficacy of semiconductors as photo-catalysts. The integration of properties of multi-walled carbon nanotubes (MWCNTs) with semiconductors is considered as imperative alternative strategy to boast the photocatalytic efficiency. The combinative merits of composites of MWCNTs and various semiconductor materials give new vista for water treatment and environmental protection. This review describes the scope of different types of MWCNT and semiconductor composites as photo-catalysts and their structure-property relationships in oxidative degradation and mineralization of organic pollutants, in particular.

Oxygen vacancy-mediated WO3 nanosheets by etched {200} facets and the efficient visible-light photocatalytic oxygen evolution

The abundant oxygen vacancies in WO₃ nanosheets result in the significant improvement of the photocatalytic O₂ evolution.

In-situ synthesis of rGO-ZnO nanocomposite for demonstration of sunlight driven enhanced photocatalytic and self-cleaning of organic dyes and tea stains of cotton fabrics

Recently, research activities are focused on development of 2D reduced graphene oxide (rGO) based semiconductor nanocomposite materials for boosting up its catalytic applications. In this work, a rarely reported green synthesis approach has been envisioned to synthesize in-situ 2D rGO-ZnO (rGZn) nanocomposites from Apple juice and zinc acetate. Also the composition of the samples has been optimized to achieve high photocatalytic and self-cleaning properties by the formation of reactive oxidation species. The samples are characterized for their microstructural, optical absorption and photoluminescence properties. It has been tested that rGZn nanocomposites are capable of removing a test dye, namely methylene blue (MB) from water and achieved the highest dye degradation efficiency of ∼91% within only 60 min under UV-vis light irradiation. A smart cotton fabric (CF) coated with rGZn has been prepared and demonstrated its photocatalytic self-cleaning property by degradation of MB, rhodamine B dyes and tea stains on it even under sunlight irradiation, which is scarcely available in the literature. Therefore, this work may open a new avenue of research for low cost and easy synthesis of rGO-semiconductor nanocomposites with high photocatalytic properties for industrial applications as well as for development of rGO based smart fabric for real-life applications.

Carbon dots-decorated Na2W4O13 composite with WO3 for highly efficient photocatalytic antibacterial activity

Photodisinfection by semiconductors has been proven to be an effective method for achieving antibacterial or antifungal activity. However, the toxicity of the nanomaterial to the environment and organisms is a major concern. Herein, a highly efficient and environmentally friendly photodisinfection material of a carbon dots (CDs) decorated Na₂W₄O₁₃ composite with WO₃ photocatalyst was fabricated via a facile hydrothermal-calcination approach. The TEM (transmission electron microscopy) images showed that CDs decorated the surface of the Na₂W₄O₁₃ flakes. Compared with the samples without incorporated CDs, the as-synthesized composite of CDs/Na₂W₄O₁₃/WO₃ exhibited excellent antimicrobial activity against E. coli under visible light illumination. Electron spin resonance (ESR) spectroscopy and reactive species scavenging experiments revealed that the hydroxyl radicals and superoxide radical anions played the most important role in the photocatalytic bacterial inactivation. Furthermore, the cytotoxicity of the CDs/Na₂W₄O₁₃/WO₃ composite was evaluated by analyzing the viability of HepG2 and Chinese hamster lung (V79) cells using Cell Counting Kit-8 (CCK-8).

Well-controlled in-situ growth of 2D WO3 rectangular sheets on reduced graphene oxide with strong photocatalytic and antibacterial properties

Finding the materials, which help to control the water pollution caused by organic and bacterial pollutants is one of the challenging tasks for the scientific community. 2D sheets of WO₃ and composite of WO₃ and reduced graphene oxide (rGO) have been synthesized in a well-controlled way using a hydrothermal method. The as synthesized 2D sheet of WO₃ and rGO-WO₃ composite were characterized by various techniques. The 2D sheets of WO₃ and rGO-WO₃ composite are efficiently utilized for the photocatalytic degradation of methylene blue (MB) and Rhodamine B (RhB) dyes under sunlight. The rGO-WO₃ composite reveals excellent photocatalytic degradation of RhB dye by degrading it upto 85% under sunlight. However, the MB dye was degraded by 32%. The greater degradation of RhB dye was explained in terms of the molecular electrostatic potential. We found that RhB has a more positive potential compared to MB dye where O₂^- and OH^̊ radicals interact more strongly, resulting in a greater degradation of the RhB dye. The antibacterial activity of the 2D sheets of WO₃ and rGO-WO₃composite was also investigated on gram positive (B. subtilis) and gram negative (P. aeroginosa) microbes for the first time.

Synthesis and Characterization of WO₃/Graphene Nanocomposites for Enhanced Photocatalytic Activities by One-Step In-Situ Hydrothermal Reaction

Tungsten trioxide (WO₃) nanorods are synthesized on the surface of graphene (GR) sheets by using a one-step in-situ hydrothermal method employing sodium tungstate (Na₂WO₄·2H₂O) and graphene oxide (GO) as precursors. The resulting WO₃/GR nanocomposites are characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirm that the interface between WO₃ nanorod and graphene contains chemical bonds. The enhanced optical absorption properties are measured by UV-vis diffuse reflectance spectra. The photocatalytic activity of the WO₃/GR nanocomposites under visible light is evaluated by the photodegradation of methylene blue, where the degradation rate of WO₃/GR nanocomposites is shown to be double that of pure WO₃. This is attributed to the synergistic effect of graphene and the WO₃ nanorod, which greatly enhances the photocatalytic performance of the prepared sample, reduces the recombination of the photogenerated electron-hole pairs and increases the visible light absorption efficiency. Finally, the photocatalytic mechanism of the WO₃/GR nanocomposites is presented. The synthesis of the prepared sample is convenient, direct and environmentally friendly. The study reports a highly efficient composite photocatalyst for the degradation of contaminants that can be applied to cleaning up the environment.

Crystal transformation of 2D tungstic acid H2WO4 to WO3 for enhanced photocatalytic water oxidation

New photocatalytic materials for stable reduction and/or oxidization of water by harvesting a wider range of visible light are indispensable to achieve high practical efficiency in artificial photosynthesis. In this work, we prepared 2D WO₃·H₂O and WO₃ nanosheets by a one-pot hydrothermal method and sequent calcination, focusing on the effects of crystal transformation on band structure and photocatalytic performance for photocatalytic water oxidation in the presence of electron acceptors (Ag⁺) under simulated solar light irradiation. The as-prepared WO₃ nanosheets exhibit enhanced rate of photocatalytic water oxidation, which is 6.3 and 3.6 times higher than that of WO₃·H₂O nanosheets and commercial WO₃, respectively. It is demonstrated that the releasing of water molecules in the crystal phase of tungstic acid results in transformation of the crystal phase from orthorhombic WO₃·H₂O to monoclinic WO₃, significantly improving the activity of photocatalytic water oxidation in the presence of Ag⁺ because the shift-up of conduction band of WO₃ matches well with the electrode potential of Ag⁺/Ag(s), leading to efficient separation of photoinduced electrons and holes in pure WO₃ nanosheets.

Tailoring of enhanced interfacial polarization in WO3 nanorods grown over reduced graphene oxide synthesized by a one-step hydrothermal method

In the present report, well-defined WO₃ nanorods (NRs) and a rGO–WO₃ composite were successfully synthesized using a one-pot hydrothermal method.

Efficient conversion of fructose into 5-hydroxymethylfurfural over WO3/reduced graphene oxide catalysts

A sustainable and efficient catalyst for converting carbohydrates to a renewable platform chemical 5-hydroxymethylfurfural (HMF) is the goal in the study of biomass recycling.

Construction of WO3–g-C3N4 composites as efficient photocatalysts for pharmaceutical degradation under visible light

Simple construction of WO₃–g-C₃N₄ Z-scheme heterojunctions as efficient photocatalysts to degrade sulfamethoxazole, which is one of the most commonly used pharmaceuticals.

Fabrication of MoS2/WO3 nanocomposite films for enhanced electro-chromic performance

A novel MoS₂ nanocomposite for electrochromic devices was synthesized, showing enhanced transmittance variation, colouration efficiency and switching times.

Fabrication of WO2.72/RGO nano-composites for enhanced photocatalysis

WO_2.72/RGO nano-composites exhibit remarkable photocatalytic activity in both oxygen evolution from water splitting and selective oxidation of benzyl alcohol due to the synergetic effects between WO_2.72 and RGO.