Pristine Bi2WO6 Research Articles

Novel S-scheme derived Mo–Bi2WO6/WO3/Biochar composite for photocatalytic removal of Methylene Blue dye

Presently, the distinct charge transport and interface interaction of the S-scheme heterojunction has garnered significant interest. Herein, a S-scheme-based charge transportation Mo-doped Bi2WO6/WO3/Biochar heterojunction was synthesized in situ using a coprecipitation technique to improve methylene blue adsorption and photocatalytic reactive oxygen species production. The doped Mo altered the band gap of Bi2WO6 to increase light absorption, which can facilitate electron-hole separation and transfer. Likewise, the S-scheme band structure improved sunlight utilization, enhanced the reduction and oxidation power of photogenerated electrons, and boosted charge carrier separation and transfer. Thus, due to the synergetic impact of doping and the S scheme band structure, the photocatalysts efficiently eliminated Methylene blue up to 87.5 % in 30 min of photoirradiation. Fabricated heterojunction Mo–Bi2WO6/WO3/Biochar photocatalyst have highest Kapp values 0.02816 min−1 while Mo–Bi2WO6/WO3, Mo–Bi2WO6, Bi2WO6, and WO3 photocatalysts have 0.02816, 0.02273, 0.01527, 0.00643, and 0.00735 min−1, respectively which was 4.38 times greater than pristine Bi2WO6. The study offers a novel perspective for the in-situ production of S-scheme heterojunction with doping to remove different types of contaminants.

Photoelectrocatalytic degradation of organic contaminants by spray coated Z-scheme TiO2/Bi2WO6 heterostructure electrode under solar light

This study demonstrates that spray deposited layered TiO2/Bi2WO6 heterostructure photoelectrodes exhibit strong interfacial interactions, leading to significant enhancements in photoelectrochemical performance. Time-resolved photoluminescence (TRPL) spectra indicated a prolonged lifetime of photoinduced carriers. The red shift in the absorption edge of TiO2/Bi2WO6 improved the visible light harvesting capability of Bi2WO6. Nyquist plots showed effective charge separation, and the TiO2 layer at the bottom significantly influenced the flat band potential compared to pristine Bi2WO6, as evidenced by Mott-Schottky analysis. This configuration improved the separation of photogenerated charge carriers via a Z-scheme charge transfer mechanism. The TiO2/Bi2WO6 electrode demonstrated a higher efficiency of 94% for methylene blue degradation within 160 min, compared to pure Bi2WO6. Quenching experiments confirmed the Z-scheme charge transfer mechanism in the coupled TiO2/Bi2WO6 heterojunction during degradation reactions. This study highlights the benefits of semiconductor coupling with different band potentials, promoting large-scale applications of solar-driven TiO2/Bi2WO6 photoelectrodes for environmental remediation.

Enhanced Hg(II) reduction activity over two-dimensional n-n heterojunction MoS2/Bi2WO6 nanocomposites under visible light illumination

The engineering of band structure acts as an effective avenue to promote photocatalytic redox reactions, which can be achieved by fabricating heterojunction photocatalysts. Herein, MoS2 NPs were anchored on the surface of the mesoporous Bi2WO6 network through a facile sol-gel process to form heterostructure MoS2/Bi2WO6 nanocomposites. HR-TEM and XRD results of the obtained MoS2/Bi2WO6 nanocomposite verified the formation of the hexagonal phase of MoS2 and the Bi2WO6 in the orthorhombic phase. The MoS2/Bi2WO6 nanocomposites displayed enhancement harvest in the visible light domain and photocatalytic ability in comparison with the pristine Bi2WO6. The photocatalytic ability of MoS2/Bi2WO6 nanocomposites was assessed by the Hg(II) reduction upon visible light irradiation. The optimal 12% MoS2/Bi2WO6 photocatalyst displayed the superior reduction of Hg(II) about 99% after 50 min, and the rate constant reached 0.1220 min-1 according to pseudo-first-order kinetic, where it was larger three folds than pristine Bi2WO6 (0.0418 min-1). The outstanding photocatalytic ability of n-n heterojunction MoS2/Bi2WO6 photocatalyst was accredited to the huge surface area, wide photoabsorption, and high separation efficiency of photocarriers. The reduction ability of MoS2/Bi2WO6 photocatalyst remained at 94% in the recycle five times, indicating its good reusability and high stability. The obtained heterojunction with the S-scheme mechanism could inhibit the recombination of the photocarriers, thus leading to superb photocatalytic ability. This work emerges an efficient route to design S-scheme heterojunction Bi2WO6-based photocatalytic methods for energy conversion and environmental purification.

Ti3C2Tx/Bi2WO6 composite nanomaterials for triethylamine detection at room temperature

Low-power triethylamine (TEA) detection at room temperature (RT) is becoming increasingly significant in practical scenarios. As a novel two-dimensional material, Ti3C2Tx MXene has a high potential in the field of chemical sensing at RT. It is essential to acquire the composition of the surface functional groups for Ti3C2Tx since the surface chemistry is crucial for a strong interplay between the target gas and Ti3C2Tx. In this work, the surface functional groups were quantitatively evaluated (approximately 40 % -O, 60 % -F) based on the combined usage of XPS analysis and DFT simulations. Ti3C2F1.2O0.8 was determined to be metallic according to the calculated total density of states and band structure. A metal-semiconductor-type composite nanostructures based on the single/few-layer Ti3C2Tx and Bi2WO6 microcages were fabricated with different Ti3C2Tx mass percentages. 0.1 wt% Ti3C2Tx/Bi2WO6 composite demonstrates a response enhancement by 52 % compared with the pristine Bi2WO6 in the detection of 500 ppm TEA at RT. Besides, the sensitization mechanism is ascribed to the abundant surface functional groups and the catalytic effect of Ti3C2Tx.

Synthesis and characterization of Ag/Cu dual-metal-functionalized porous Bi2WO6 microsphere with enhanced N2 photofixation

Semiconductor photocatalytic nitrogen reduction reaction (PNRR) stands as a promising clean technique for ammonia synthesis, yet it confronts numerous challenges. In this study, Ag nanoparticle-modified Cu-doped Bi2WO6 (ACB) porous composite materials with varying mass percentages were successfully synthesized using a solvothermal reduction approach. The incorporation of transition metal Cu effectively modulates the energy band position of Bi2WO6. Furthermore, the introduction of Ag nanoparticles significantly suppresses the recombination of photogenerated carriers. Without adding sacrificial agent, the photocatalytic nitrogen fixation yield of ACB reaches an impressive 184.93 μmol·g−1·h−1, which is 5.44 times higher than that of pristine Bi2WO6. A comprehensive analysis of the experimental results reveals that the combined effect of Cu doping and Ag nanoparticle loading endows ACB with an increased exposure of active sites, thereby significantly enhancing its photocatalytic nitrogen fixation performance. This research offers a promising approach for the design of metal nanoparticle-supported catalysts for PNRR, holding significant implications for the advancement of other material systems.

Robust photoelectrocatalytic degradation of antibiotics by organic-inorganic PDISA/Bi2WO6 S-scheme heterojunction membrane

Ensuring the stability of the photoelectrode is paramount for optimal photoelectrocatalysis performance. In this investigation, a hybrid nanofiber film, incorporating the π-π conjugated self-assembly of perylene diimide monomers (PDISA) with Bi2WO6 (PDISA/Bi2WO6), was fabricated through the electrospinning process. Subsequently, this flexible electrospun film was pressed onto a Ni mesh to create a robust PDISA/Bi2WO6 electrode membrane. Results from photoelectrocatalytic studies reveal that the devised PDISA/Bi2WO6 photoanode significantly enhances the photoelectrocatalytic degradation efficiency of tetracycline (TC) and ciprofloxacin (CIP). Specifically, the apparent rate constants for the photoelectrocatalytic degradation of TC by 30%PDISA/Bi2WO6, compared to pristine PDISA and Bi2WO6, are elevated by 1.9 and 2.0 times, respectively. Moreover, the reaction rates of the photoelectrocatalytic (PEC) process surpass those of photocatalysis (PC) and electrocatalysis (EC) by 1.9 times and 8.0 times, respectively. Impressively, even after five cycles of PEC degradation of TC, the photoelectrode maintains 98.4% of its initial degradation rate, indicating its exceptional stability. These improvements in degradation efficiency and stability are attributed to the creation of the PDISA/Bi2WO6 S-scheme heterojunction membrane photoanode and the synergistic effects of photoelectrocatalysis.

Defect Engineering of Bi2WO6 for Enhanced Photocatalytic Degradation of Antibiotic Pollutants.

Infiltration of excessive antibiotics into aquatic ecosystems plays a significant role in antibiotic resistance, a major global health challenge. It is therefore critical to develop effective technologies for their removal. Herein, defect-rich Bi2WO6 nanoparticles are solvothermally prepared via epitaxial growth on pristine Bi2WO6 seed nanocrystals, and the efficiency of the photocatalytic degradation of ciprofloxacin, a common antibiotic, is found to increase markedly from 62.51% to 98.27% under visible photoirradiation for 60min. This is due to the formation of a large number of structural defects, where the synergistic interactions between grain boundaries and adjacent dislocations and oxygen vacancies lead to an improved separation and migration efficiency of photogenerated carriers and facilitate the adsorption and degradation of ciprofloxacin, as confirmed in experimental and theoretical studies. Results from this work demonstrate the unique potential of defect engineering for enhanced photocatalytic performance, a critical step in removing antibiotic contaminants in aquatic ecosystems.

Pt-loaded Bi2WO6 microdiscs for highly sensitive and selective triethylamine monitoring

Pt-loaded curling-like Bi2WO6 (BWO) microdiscs were fabricated via a simple one-step hydrothermal and impregnation route. Various characterization methods, such as XRD, EDS and TEM, were conducted to prove the successful Pt loading. Electron migration from the semiconductor BWO to the precious metal Pt was revealed by the blue shift of the Bi 4f and W 4f XPS peaks with the increase of the Pt loading amount and the ∼10-fold baseline resistance elevation of the BWO-based sensor by the Pt loading, proving the formation of Schottky junction. Among the pristine BWO and Pt-loaded BWO with different Pt loading amounts, 1 wt % Pt-loaded BWO exhibits the highest gas response of 209 in sensing 500 ppm triethylamine at 300 °C, a minimal selectivity coefficient of 130.6 against some typical interfering gases at the same concentration and a low detection threshold of 1 ppm. Additionally, the sensitization mechanism is discussed as the synergistic effect of noble metal catalytic effect and metal-semiconductor junctions.

Construction of fast charge-transferred 0D/2D BiOBr/Bi2WO6 S-scheme heterojunction with enhanced photocatalytic performance

Novel Bi-based photocatalysts play an increasing role in dealing with environmental pollution and resource shortages. Among these Bi-based materials, BiOBr and Bi2WO6 have gained intensive attraction due to the appropriate energy band alignments and their anisotropic crystal structure. 0D/2D BiOBr/Bi2WO6 heterojunction was constructed by depositing BiOBr nanoparticles on few-layer Bi2WO6 nanosheets. The structure, optical property, and micromorphology of samples were characterized by XRD, XPS, UV–vis DRS, SEM, TEM, and AFM. The photoluminescence, photocurrent density, and electrochemical impedance spectroscopy (EIS) as well as the transient surface photovoltage (TSPV) were performed to explore the transfer of photoinduced charge carriers. The photocatalytic efficiency of the heterojunction is much improved, about 2.67 folds higher than that of pristine Bi2WO6. The fast separation and migration and the prolonged lifetime of photogenerated carriers in the BiOBr/Bi2WO6 heterojunction are validated by photoelectrochemical tests. The influence factors, versatility, and reusability of the heterojunction are also evaluated. Radical trapping test reveals that h+ and ·O2− are predominant active species and make a major contribution to the photoactivity of the BiOBr/Bi2WO6 heterojunction. The formed energy-band bending, the built-in electric field, and the S-scheme charge transfer strategy are thermodynamically and kinetically favorable for the photoactivity and stability of the heterojunction.

Influence of cerium and iron substitution on the Bi2WO6 hierarchical microsphere and their enhanced photocatalytic degradation performance

A facile hydrothermal approach was employed to synthesize cerium and iron co-doped Bi2WO6 photocatalysts, and their photocatalytic performance for the degradation of cationic rhodamine B (RhB) and thionine (TH) dyes under UV–visible light illumination was investigated. Powder XRD investigation revealed that the Ce and Fe ions significantly influenced the Bi2WO6 crystal structure, while HR-XPS confirmed the valence states of Ce and Fe ions in the Bi2WO6 lattice. The light absorption wavelength of the co-doped samples was red-shifted when compared to the pristine Bi2WO6. The photoluminescence spectroscopy results showed that the synergistic effect of the Ce–Fe intermediate state in the Ce–Fe co-doped Bi2WO6 photocatalyst significantly reduced the recombination of photoinduced electron-hole pairs and boosted photocatalytic degradation activity. Furthermore, the stability of the best-performed catalyst was verified using recycling tests. The degrading efficiency of TH and RhB was not significantly affected after five repeated cycles. A potential mechanism for increased photocatalytic activity was also discussed.

Ultrathin RuO2/Bi2WO6 and PtO2-Pt/Bi2WO6 heterojunction nanosheets toward efficient photocatalytic CO2 reduction under visible light irradiation

Ultrathin RuO2/Bi2WO6 and PtO2-Pt/Bi2WO6 heterojunction nanosheets with superior (001) crystal planes were successfully constructed by combining a hydrothermal process with photo-deposition technique, which present efficient photocatalytic reduction of CO2 into CO and CH4 under visible light irradiation. Under the irradiation of 420 nm monochromatic light, the apparent quantum yield (AQY) of RuO2/Bi2WO6 reached to 0.21 %, which was about 1.2 times that of PtO2/Pt-Bi2WO6 (0.17 %) and 1.9 times that of pristine Bi2WO6 (0.11 %), respectively. After decorated RuO2 or PtO2-Pt QDs on Bi2WO6 nanosheets to form local heterojunctions including a type II p-n heterojunction RuO2/Bi2WO6 or PtO2/Bi2WO6, as well a Schottky junction Pt/Bi2WO6, RuO2/Bi2WO6 exhibited a higher photocatalytic activity and selectivity of CH4 evolution (33.95 %) than PtO2-Pt/Bi2WO6 (20.9 %), due to the synergetic effect of following factors including enhanced absorption of visible light, improved separation efficiency of charge carrier, reduced charge transfer resistance, enlarged reduction drive ability of photo-induced electrons, accelerated surface catalytic reaction kinetics, and improved specific surface and pore volume. This work provides guidance for designing and developing novel Bi2WO6-based photocatalysts for selective photocatalytic CO2 reduction into target reaction.

Chelating Agent‐Assisted‐Bi2WO6 Nanostructured Materials for Electron Transfer‐Driven Ultrafast Catalytic Reduction of Organic and Inorganic Contaminants

AbstractWe report a chelating agent‐assisted synthesis of Bi2WO6 nanomaterials using a facile hydrothermal method. The presence of a chelating agent (EDTA) influences the degree of crystallinity, morphology, and surface area of Bi2WO6. Analysis by electron microscopy revealed morphological changes of Bi2WO6 from flower‐like to multilayered disc‐like structures after introducing EDTA. The surface area of pristine Bi2WO6 NMs is significantly increased from 31 to 50 m2 g−1. We demonstrated the catalytic properties of Bi2WO6 and EDTA‐Bi2WO6 for 4‐nitrophenol (4‐NP), methyl orange (MO), congo red (CR), and [Fe(CN)6]3− reductions in the presence of NaBH4. It was observed that EDTA‐Bi2WO6 exhibited higher catalytic activity compared to the pristine Bi2WO6 NMs. The reduction reactions followed pseudo‐first‐order kinetics and the rate constant values of EDTA‐Bi2WO6 for 4‐NP, MO, CR, and [Fe(CN)6]3− reductions were found to be 0.847, 0.584, 0.702, and 0.463 min−1, respectively. The reduction proceeds through electron transfer process over an EDTA‐Bi2WO6 catalyst in the presence of NaBH4. Furthermore, EDTA‐Bi2WO6 also showed ultrafast catalytic performance to dichromate (Cr2O72−) reduction, compared to pristine Bi2WO6. The EDTA‐Bi2WO6 catalyst could be recycled up to five times without undergoing a significant loss in activity.

Sol-gel synthesis of photoactive PtO/Bi2WO6 nanocomposites for improved photoreduction of Hg (II) ions under visible illumination

Heterostructure semiconductor photocatalysts have attracted much research interest for wastewater remediation under visible irradiation. The current study describes synthesizing and characterizing novel nanocomposites based on a mesoporous Bi2WO6 with variation PtO amount through a sol-gel procedure. The effect of PtO content on structural, optical, and photocatalytic features was thoroughly discussed. The Hg(II) ions photocatalytic reduction was utilized to evaluate the performance of the constructed heterojunctions under visible irradiation, in the presence of formic acid as a hole scavenger. The most efficient 1.5wt% PtO/Bi2WO6 nanocomposite demonstrated 100% reduction within 60 min with the greatest photoreduction rate constant (0.062 min−1), which was approximately 5.16 folds greater than pristine Bi2WO6 (0.012 min−1). The enhanced efficiency of the developed heterojunctions in the photoreduction of Hg(II) ions could be attributed to the incorporating 1.5wt% PtO, which increases the light-harvesting, decrease the bandgap (Eg) to 2.23 eV, boost the isolation and mobility of the photoexcited carriers. Utilizing a 1.6 g/L of 1.5wt% PtO/Bi2WO6 nanocomposite demonstrated complete photoreduction efficiency after 40 min and outstanding stability after five cycles without losing their photocatalytic activity. This study offers a cost-effective method of producing Bi2WO6 -based nanocomposites with remarkable ability in wastewater remediation.

Optimization of Intercalated 2D BiOCl Sheets into Bi2WO6 Flowers for Photocatalytic NH3 Production and Antibiotic Pollutant Degradation.

Photocatalytic N2 fixation is a complex reaction, thereby prompting researchers to design and analyze highly efficient materials. Herein, one-pot hydrothermal Bi2WO6-BiOCl (BW-BiOCl) heterojunctions were synthesized by varying the molar ratio of tungsten: chlorine precursor. Major morphological transformations in BiOCl were observed wherein it turned from thick sheets ∼230 nm in pure BiOCl to ∼30 nm in BW-BiOCl. This was accompanied by extensive growth of {001} facets verified from X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) analyses. A p-n heterojunction was formed between Bi2WO6 and BiOCl evidenced via photoluminescence (PL), time-resolved photoluminescence (TRPL), photocurrent response, and electrochemical impedance spectroscopy (EIS) analyses. The formation of heterojunction between Bi2WO6 and BiOCl led to the reduction of the work function in the BW-BiOCl 0.25 hybrid confirmed via ultraviolet photoelectron spectroscopy (UPS) analysis. BW-BiOCl 0.25 could produce ammonia up to 345.1 μmol·L-1·h-1 owing to the formation of a robust heterojunction with an S-scheme carrier transport mechanism. Recycle tests resulted in no loss in N2 reduction activities with post-catalytic analysis, showcasing the high stability of the synthesized heterojunction. Novel performance was owed to its excellent chemisorption of N2 gas on the heterojunction surface verified by N2-temperature programmed desorption (TPD). BW-BiOCl 0.25 also displayed a superior rate constant of 3.03 × 10-2 min-1 for 90 min CIP degradation time, higher than pristine BiOCl and Bi2WO6. Post-photocatalytic Fourier transform infrared (FTIR) spectroscopy of BW-BiOCl 0.25 revealed the presence of C-H stretching peaks in the range of 2850-2960 cm-1 due to adsorbed CIP and methanol species in CIP degradation and N2 fixation, respectively. This also confirmed the enhanced adsorption of reacting species onto the heterojunction surface.

Polyurethane sponge assisted recoverable photocatalyst for outdoor weak sunlight-driven efficient water purification

Photocatalysis is an effective technology to address wastewater issue. However, the difficult recoverability of sample powders and poor degradation performance of catalysts under weak sunlight irradiation restrict the commercialization applications. In this work, the Bi2WO6/g-C3N4 heterojunction is synthesized by hydrothermal and calcination techniques, and a three-dimensional polyurethane sponge is introduced to assist the catalyst powder. On the one hand, weather variations produce less affection for Bi2WO6 sample, which exhibits the efficient photocatalytic activity driven by weak sunlight. The construction of Bi2WO6/g-C3N4 heterojunction speeds up separation and transfer of photogenerated carriers, further improving the catalytic performances of pristine Bi2WO6. Under cloudy (solar power density 21.93–52.97 mW/cm2) and overcast (solar power density 3.66–18.99 mW/cm2) weathers, tetracycline degradation efficiencies of Bi2WO6/g-C3N4 reach 64.66% and 55.19% after 150 min of sunlight irradiation, respectively. On the other hand, catalyst powder is tightly loaded onto the surface of polyurethane sponge via polyurethane waterproof coating, which is convenient for material recovery and reuse. After 4 cycles, tetracycline degradation efficiencies of Bi2WO6/g-C3N4 present no significant decrease, saving reaction cost and causing no secondary pollution to water environment. This work provides a promising candidate for large-scale commercialization applications of wastewater treatment.

A facile two-step hydrothermal preparation of 2D/2D heterostructure of Bi2WO6/WS2 for the efficient photodegradation of methylene blue under sunlight

A facile two-step hydrothermal method was successfully used to prepare a photocatalyst Bi2WO6/WS2 heterojunction for methyl blue (MB) photodegradation. Fabricated photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). Band gap measurements were carried out by diffuse reflectance spectroscopy (DRS). Results indicated that the prepared heterostructure photocatalyst has increased visible light absorption. Photocatalytic performance was evaluated under sunlight irradiation for methylene blue (MB) degradation as a model dye. Variations in pH (4–10), amount of catalyst (0.025–0.1 g/L), and initial MB concentrations (5–20 ppm) were carried out, whereas all prepared catalysts were used to conduct the tests with a visible spectrophotometer. Degradation activity improved with the pH increase; the optimum pH was approximately 8. Catalyst concentration is directly related to degradation efficiency and reached 93.56% with 0.075 g of the catalyst. Among tested catalysts, 0.01 Bi2WO6/WS2 has exhibited the highest activity and a degradation efficiency of 99.0% in 40 min (min) for MB. MB photodegradation follows pseudo-first-order kinetics, and obtained values of kapp were 0.0482 min−1, 0.0337 min−1, 0.0205 min−1, and 0.0087 min−1 for initial concentrations of 5 ppm, 10 ppm, 15 ppm, and 20 ppm, respectively. The catalyst was reused for six cycles with a negligible decrease in the degradation activity. Heterostructure 0.01 Bi2WO6/WS2 has exhibited a photocurrent density of 16 μA cm−2, significantly higher than 2.0 and 4.5 μA cm−2 for the pristine WS2 and Bi2WO6, respectively. The findings from these investigations may serve as a crucial stepping stone towards the remediation of polluted water facilitated by implementing such highly efficient photocatalysts.

Simplified synthesis of direct Z-scheme Bi2WO6/PhC2Cu heterojunction that shows enhanced photocatalytic degradation of 2,4,6-TCP: Kinetic study and mechanistic insights

For this work, we employed n-type Bi2WO6 and p-type PhC2Cu to formulate a direct Z-scheme Bi2WO6/PhC2Cu (PCBW) photocatalyst via simplified ultrasonic stirring technique. An optimal 0.6PCBW composite exhibited the capacity to rapidly photodegrade 2,4,6-TCP (98.6% in 120 min) under low-power blue LED light, which was 8.53 times and 12.53 times faster than for pristine PhC2Cu and Bi2WO6, respectively. Moreover, electron spin resonance (ESR), time-resolved PL spectra, and quantitative ROS tests indicated that the PCBW enhanced the separation capacity of photocarriers. It also more readily associated with dissolved oxygen in water to generate reactive oxygen species (ROS). Among them, the ability of PCBW to produce ·O2- in one hour was 12.07 times faster than for pure PhC2Cu. In addition, the H2O2 formation rate and apparent quantum efficiency of PCBW are 10.73 times that of PhC2Cu, which indicates that PCBW not only has excellent photocatalytic performance, but also has outstanding ROS production ability. Furthermore, Ag photodeposition, in situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations were utilized to determine the photogenerated electron migration paths in the PCBW, which systematically confirmed that Z-scheme heterojunction were successfully formed. Finally, based on the intermediate products, three potential 2,4,6-TCP degradation pathways were proposed.

F-doped Bi2WO6 with rich oxygen vacancies for boosting photo-oxidation/reduction activity

The erythrocyte-like F-doped Bi2WO6 (F-Bi2WO6) with rich oxygen vacancies was fabricated via a simple one-step hydrothermal method. With the help of various characterization techniques, it was determined that F− anions were doped into the Bi2WO6 lattice together with the generation of oxygen vacancies in the doping process. The oxygen vacancy as an electron acceptor in Bi2WO6 could tune band structure and trap the electrons easily to generate a new quick channel of electron transport, thus promoting the separation and transfer of e−-h+ pairs. The F-Bi2WO6 photocatalysts exhibited superior properties in photocatalytic activity, photocarrier separation and visible-light absorption compared with the pristine Bi2WO6. And the optimized F1.00-Bi2WO6 displayed a remarkable 1.6 and 2.5 times enhanced photocatalytic Cr(VI) reduction and MO degradation activities than the pristine Bi2WO6, respectively. Consequently, the enhanced photocatalytic mechanisms were elaborated for the Cr(VI) reduction and MO degradation under visible-light, respectively.

Facile synthesis of hierarchical S-scheme In2S3/Bi2WO6 heterostructures with enhanced photocatalytic activity

Construction of heterojunction photocatalysts is a valid tactics to boost the photocatalytic property of catalyst. Herein, a novel S-scheme heterojunction of zero/three dimensional (0D/3D) In2S3/Bi2WO6 hybrid catalyst was obtained by assembling In2S3 nanoparticles on floriated shaped Bi2WO6 microsphere through a simple precipitation route for the first time. The morphology, structures, composition, chemical and optical properties of the resulting materials were carefully researched through various instruments. The degradation experiments revealed that In2S3/Bi2WO6 composites exhibited superior photocatalytic behavior for dyes decomposition. The optimized In2S3/Bi2WO6 composite showed remarkable photocatalytic decomposition Rhodamine B (RhB) and Methylene blue (MB), 16.0 (2.68)-fold and 70.3 (1.66)-fold larger than that of pristine Bi2WO6 (In2S3), and it also possessed good stability and reusability. The largely improved photoactivity may derive from the formed S-scheme heterojunction between Bi2WO6 and In2S3, which accelerated photocarriers disassociation and retained strong redox power. Liquid chromatography-mass spectrometry (LC-MS) was applied to reveal the RhB decomposition pathway. Besides, the S-scheme charge transfer mechanism was well elucidated based on in-situ X-ray photoelectron spectroscopy analysis, density functional theory calculation (DFT), and trapping experiment along with electron paramagnetic resonance (EPR) tests.

Superior photopiezocatalytic performance by enhancing spontaneous polarization through post-synthesis structure distortion in ultrathin Bi2WO6 nanosheet polar photocatalyst

The internal polarizations of polar photocatalysts could be enhanced through unit cell structure modulations to improve their photocatalytic performances. In this work, a simple, robust and low-cost NaOH etching process is developed to treat ultrathin Bi2WO6 nanosheets after their creation, resulting in a higher degree of polyhedron distortion (∼141 %) and an enhanced piezoelectricity (∼260 % the maximum effective piezoelectric coefficient d33). Compared with pristine ultrathin Bi2WO6 nanosheets, these etched samples demonstrate an improved charge carrier separation and transfer behavior due to their enhanced internal polarization with the assistance of richer oxygen vacancies, which largely enhance their piezocatalysis (∼4.6 times), photocatalysis (∼14.3 times) and especially coupled photopiezocatalysis (∼33.9 times) performances as demonstrated in their sulfamethoxazole (SMX) degradation performances. ·O2–, 1O2 and h+ are proven to be main reactive oxygen species (ROSs) during their photopiezocatalytic process and they could also work well in the real water matrix.