Excellent Photocatalytic Efficiency Research Articles

Construction of C/ZnO/BiOI photocatalyst for enhanced degradation of carbaryl: Characterization, performance and mechanism

Pesticide residues lead to increasingly serious harmful ecological environment, which poses tremendous threats on human health. To overcome this problem, researchers are focusing on the development of highly efficient composites with excellent photocatalytic efficiency. In this work, a new C/ZnO/BiOI photocatalyst was successfully synthesized using hydrothermal, hydrolysis and ultrasonic technique for carbaryl degradation. The as-prepared photocatalyst was characterized by XRD, FT-IR, XPS, SEM, TEM, BET, UV–vis DRS and PL. The photocatalyst exhibited better carbaryl removal performances than that of ZnO, C/ZnO and ZnO/BiOI under simulated sunlight irradiation, which might be attributed to the efficient electron-hole separation and wider region of light response. The optimum C/ZnO/BiOI (20%) composite exhibited the highest degradation efficiency (62.9%) of carbaryl and excellent cycling stability. Reactive species scavenging and ESR experiments illustrated that . OH was the most important active species. Furthermore, the identification of intermediates revealed possible degradation pathways of carbaryl. • A new C/ZnO/BiOI photocatalyst was successfully synthesized. • The photocatalyst showed excellent photocatalytic activity and reusability. • . OH played a major role in the carbaryl degradation process. • The degradation mechanism and pathways of carbaryl were proposed.

Interface Cd-N bond bridge accelerating charge separation to the enhanced visible light driven hydrogen production from water splitting on polyaniline@Cd-Zn-S photocatalyst

The key to the industrialization of eco-friendly hydrogen production from visible light driven water splitting is the development of photocatalyst with high performance and superior stability. Herein, a novel core-shell structure polyaniline@Cd-Zn-S (Cd/Zn = 0.8/0.2) nanorod photocatalyst with the shell thickness at ∼3 nm was constructed successfully. With polyaniline served as core, the construction of polyaniline@Cd-Zn-S reduced the charge transfer resistance and released reactive sites maximumly which could benefit the hydrogen production. The constructed polyaniline@Cd-Zn-S exhibited excellent photocatalytic hydrogen production efficiency and stability with the assistance of interface Cd-N bonds. The introduction of Cd-N bonds at the interface was inferred by both experimental and DFT simulated results. It served as the bridge between shell Cd-Zn-S and core polyaniline and promoted the directional transmission and efficient separation of photo generated charge carriers. Meanwhile, the improved directional transmission of photogenerated holes restricted photo corrosion effect of the Cd-Zn-S effectively and contributed to the photocatalytic stability. The hydrogen production without any cocatalyst increased more than 6 times to 721 μmol·h−1 after the construction of core-shell structure, and remain stable for 12 consecutive hours without photocatalytic performance reduction. This work proposed a new inspiring structural model for hetero junction construction of photocatalyst, and brought an interesting enlightenment to the development of eco-friendly hydrogen production technology.

Hollow core-shell Z-scheme heterojunction on self-floating carbon fiber cloth with robust photocatalytic-photothermal performance

The combination of photothermal catalysis and photocatalysis is an effective method to remove Cr(VI) and degrade organic pollutants using solar energy. Herein, hollow flower-like W 18 O 49 @ZnIn 2 S 4 core-shell Z-type heterojunctions were prepared on carbon fiber cloth (CC) by two methods, hydrothermal method and solvent heat, which are easy to operate. The prepared photocatalysts showed very excellent photocatalytic degradation for the redox removal of Cr(VI) and degeneration of bisphenol A (BPA) under simulated sunlight, and the W 18 O 49 @Znln 2 S 4 /CC composites showed 95% and 100% removal of bisphenol A (BPA) and Cr(VI), respectively. The formation of Z-type heterojunctions promoted rapid carrier transfer, and the hollow structure improved light utilization, while the core-shell structure increased the interfacial area and number of active sites. In addition, the oxygen vacancies in W 18 O 49 have ligated unsaturated sites and unpaired electrons, which can lower the reaction energy barrier and promote molecular activation. The effects of different catalyst types, different pH values, and different initial concentrations of BPA on the photocatalytic performance were demonstrated. Furthermore, the W 18 O 49 @Znln 2 S 4 /CC composite exhibited excellent stability and reusability in 10 consecutive cycles of experiments. Its easy recovery and high stability imply potential practical applications, providing an effective strategy for the development of a new efficient catalyst for the treatment of wastewater and a sustainable environment. Hollow Core-Shell Z-Scheme Heterojunction on Self-Floating Carbon Fiber Cloth is synthesized by solvothermal and hydrothermal methods. It shows excellent visible light-driven photocatalytic pollutant removal efficiency due to the formation of Z-scheme heterojunctions promoting rapid charge carrier transfer, and the core-shell hollow structure improving light utilization and surface-active sites. • W 18 O 49 @ZnIn 2 S 4 /CC is synthesized as a self-floating photocatalyst. • The Z-scheme heterojunction has the advantage of promoting carrier transfer. • The hollow structure has a light reflection path and light collection capability. • It shows robust photothermal-photocatalytic performance. • W 18 O 49 @ZnIn 2 S 4 /CC can be easily recycled and reused.

A mesoporous nanofibrous BiVO4-Ni/AgVO3 Z-scheme heterojunction photocatalyst with enhanced photocatalytic reduction of Cr6+ and degradation of RhB under visible light

Inthisstudy, we fabricated a novel heterostructured BiVO4-Ni/AgVO3 nanofibers by combining the electrospinning approach and hydrothermal method. Benefiting from the synergetic strategy of Ni doping and AgVO3 coupling, the specific surface area and visible-light absorption of BiVO4-Ni/AgVO3 were both increased compared to BiVO4. Meanwhile, the separation efficiency of photogenerated carriers was effectively improved through the formed impurity energy level and heterojunction. As a result, the optimal BiVO4-Ni-1/AgVO3-25 photocatalyst exhibited excellent photocatalytic reduction efficiency of 99.7% towards Cr6+ within 80 min, and also displayed superior degradation efficiency of 98.6% towards RhB within 30 min. Moreover, a Z-scheme charge transfer mechanism was explained for BiVO4-Ni/AgVO3 according to the radical trapping experiments and band matching. The successful preparation of Z-scheme heterojunction BiVO4-based photocatalyst has essential application prospects in photocatalytic degradation of pollutants and reduction of metal ions.

Porous Photo-Fenton Catalysts Rapidly Triggered by Levodopa-Based Mussel-Inspired Coatings for Enhanced Dye Degradation and Sterilization

The advanced oxidation process of the photo-Fenton reaction can produce hydroxyl radicals with extremely strong oxidizing properties for the efficient and green degradation of various chemical and microbial pollutants. Herein, we report an approach to fabricating heterogeneous Fenton catalysts of β-FeOOH nanorods on porous substrates triggered by mussel-inspired coatings of levodopa (3,4-dihydroxy-phenyl-l-alanine, l-DOPA) and polyethylenimine (PEI) for efficient photocatalytic dyes' degradation and sterilization. The l-DOPA-based coatings not only promote the formation and immobilization of β-FeOOH nanorods on the porous substrates by strong coordination between catechol/carboxyl groups and Fe3+ but also improve the energy band structure of the Fenton catalysts through a valence band blue shift and band gap narrowing. The photo-Fenton catalysts prepared by the l-DOPA-based coatings exhibit high electron transport efficiency and improved utilization of sunlight. Only 2 h of mineralization is needed to fabricate these catalysts with excellent photocatalytic efficiency, in which the degradation efficiency of methylene blue can reach 99% within 30 min, whereas the sterilization efficiency of E. coli/S. aureus can reach 93%/94% within 20 min of the photo-Fenton reaction. Additionally, the prepared catalysts reveal a high photodegradation performance for various dyes including methylene blue, methyl blue, methyl orange, direct yellow, and rhodamine B. Furthermore, the catalysts retain high dye degradation efficiencies of above 90% after five photodegradation cycles, indicating cycling performance and good stability.

α-Bi2O3 nanoparticle and multiwall carbon nanotube hybrid with protonated g-C3N4 nanosheets for superior photocatalytic performance towards the mixed organic contaminants

In this work, a wet impregnation technique was utilized to create the novel g-C3N4/α-Bi2O3/MWCNT nanocomposite. To characterise the structure, morphological and photochemical properties of the synthesised materials, several characterization techniques were used. A certain number of α-Bi2O3 nanoparticles and MWCNT on the surface of the g-C3N4 nanosheets would improve electron hole pair separation, resulting in enhanced photocatalytic performance against mixed dye molecules. The g-C3N4/α-Bi2O3/MWCNT nanocomposite exhibits excellent photocatalytic efficiency (93.53%) for the decomposition of mixed dyes (rhodamine b (Rh B) and methylene blue (MB)), and it showed about 1.76, 2.13, 3.42, 1.24 and 1.37 times as higher than the g-C3N4, α-Bi2O3, MWCNT, g-C3N4/α-Bi2O3, g-C3N4/MWCNT nanocomposites, respectively. Meanwhile, in the recycling test, the g-C3N4/α-Bi2O3/MWCNT nanocomposite demonstrated excellent cyclic photostability after the five consecutive runs. According to the trapping experiment, superoxide radicals show a significant role in the dye decomposition process. This work provides a simple and suitable technique for making a visible-light active photocatalyst for potential practical application in wastewater treatment.

Ingenious construction of Ni(DMG)2/TiO2-decorated porous nanofibers for the highly efficient photodegradation of pollutants in water

Dyes and metal ions which are the major components of effluents from industries such as textile, paper, leather, cosmetics and plastic, prove to be the most harmful and toxic of all the contaminants. Especially, Ni2+ as colorant and methylene blue (MB) are contained in the wastewater of printing and dyeing plant. Herein, novel porous dimethylglyoxime (DMG)/TiO2/polyacrylonitrile (PAN) nanofiber mats were prepared via electrospinning to treat Ni2+ and MB mixture pollutants. The formation of red and virgulate Ni(DMG)2 on the nanofiber surface indicated that the composite possessed visible adsorption capacity (48.6895 mg g−1 in 120 min) as a benefit of the capability of DMG to sense Ni2+. Most importantly, the DMG/TiO2-decorated PAN nanofiber mats exhibited excellent photocatalytic MB degradation efficiency (97 % within 60 min) owing to the construction of heterjunctions between Ni(DMG)2 and TiO2 nanoparticles and the shortening of electron and hole transport paths by hierarchical structures. The skillful use of Ni(DMG)2 as an intermediate for photocatalytic MB degradation suggested that these functionalized nanofiber mats are promising candidates for practical application in sensing, heavy metal ion adsorption, and photocatalytic organic pollutant degradation.

Designing, characterization, and evaluation of chitosan-zinc selenide nanoparticles for visible-light-induced degradation of tartrazine and sunset yellow dyes

Employing dyes in different industrial sectors has produced a serious threat to the environment and living organisms of water bodies and land. For the decontamination of such toxic dyes, efforts have been made to develop an efficient, feasible, and low maintenance processes. In this context, chitosan-zinc selenide (CS–ZnSe) nanoparticles were prepared through chemical reduction method as the efficient photocatalysts for the decontamination of toxic dyes through photocatalysis. Photocatalyst's synthesis was confirmed with the help of FTIR spectroscopy. XRD indicated the hexagonal crystal structure of the CS–ZnSe with a crystallite size of 12 nm. SEM micrographs showed the average nano photocatalyst size as 25 nm. EDX analysis was employed to determine the elemental composition of the CS–ZnSe. An excellent photocatalytic degradation efficiency for tartrazine and sunset yellow dyes was obtained using CS–ZnSe. The results showed a 98% and 97% degradation efficiency for tartrazine dye and sunset yellow (SY) dye at optimized conditions of time (3 h), pH (5), dye concentration (30 ppm), catalyst dosage (0.09 g and 0.01 g) , and at a temperature of 35 °C. Findings of the photocatalytic degradation process fitted well with first-order kinetics for both the dyes. Rate constant, ‘K’ value was found to be 0.001362 min−1 and 0.001257 min−1 for tartrazine and SY dyes, respectively. While value for (correlation coefficient, R2) was 0.99307 and 0.99277 for tartrazine and sunset yellow dyes, respectively. Recyclability of the photocatalyst was confirmed using it for consecutive cycles to degrade organic dyes. Results showed that the CH–ZnS possesses excellent efficiency in decontaminating organic dyes from industrial wastewater.

Fabrication of ternary UiO-66(Ce)/Ag/BiOBr heterojunction for enhanced photocatalytic degradation of ketoprofen via effective electron transfer process: Pathways, DFT calculation and mechanism

Photocatalytic oxidation technique is considered as one of the most prospective approaches to solve the problem of environmental pollution. Herein, the novel ternary nanocomposite UiO-66(Ce)/Ag/BiOBr was fabricated via simple synthetic strategy. The obtained UiO-66(Ce)/Ag/BiOBr exhibited an excellent performance and photocatalytic efficiency of ketoprofen reached 93.5% after 180 min illumination. The ·OH and ·O2- were main active species and play an important role during the photocatalytic reaction. Furthermore, intermediate products and degradation pathways of ketoprofen were analyzed based on the 3D-EEM, DFT calculation and LC-MS. The possible reaction mechanism was proposed as follows: (1) the successful construction of heterojunction broadened the light absorption range to the visible light region; (2) the design of Ce-based MOFs provided more chances for electron transfer due to the Ce4+/Ce3+ cycling; (3) the combination of plasmon resonance effect, Schottky junction and effect of Ag bridge was an important strategy to accelerate charge transfer and improve photocatalytic efficiency.

Heterogeneous photocatalytic borylation of aryl iodides mediated by isoreticular 2D covalent organic frameworks

Metal-free heterogeneous photocatalysts provide an environmental-friendly and cost-efficient avenue for green organic synthesis. Covalent organic frameworks (COFs) as heterogeneous photocatalysts showcase promising potential in the field of photocatalytic organic reactions due to their high porosity, insolubility and tailor-made functions. However, thus far, COF-based catalysts only mediated a few types of reactions. Herein, we developed a series of isoreticular nitrogen-rich covalent organic frameworks (N-COFs) with comparable porous structures as photocatalysts which effectively mediated the borylation of aryl iodides with broad substrate scope. Remarkably, 6N-COF exhibits excellent photocatalytic efficiency and superior recyclability. It suggests a new pathway to construct efficient heterogeneous photocatalysts for the borylation of aryl halides.

Efficient activation of peroxymonosulfate by iron-containing mesoporous silica catalysts derived from iron tailings for degradation of organic pollutants

Solid waste and water pollution are global environmental problems that need to be urgently solved. Using industrial solid waste to treat organic pollutant wastewater might be a good strategy to solve two problems. Herein, iron tailings were used to prepare iron-containing mesoporous silica (MFS) materials under a one-step hydrothermal route. The as-prepared MFS showed excellent photocatalytic degradation efficiency and stability over a wide pH range for five typical organic pollutants. Further degradation test using tap water and Xiangjiang River water notably confirmed its practical application. Quenching and ESR experiments revealed radical (including sulfate (∙SO4−), hydroxide (·OH), and superoxide (·O2−) radicals) and non-radical (including single oxygen (1O2)) pathways worked together in the MFS/PMS/vis system. The cost estimation of the waste-derived MFS materials indicated that the raw material cost could be reduced by $129.8 per kilogram compared to the conventional method. This strategy not only provides a possible solution to iron tailings solid waste problem, but also develops a benign approach to the design and preparation of heterogeneous catalysts. The as-prepared materials have great potential in wastewater treatment, and follow the idea of treating waste with waste to achieve sustainable development.

One-dimensional recoverable ZnFe2O4/C/MnO2/BiOI magnetic composite with enhanced photocatalytic performance for organic dyes degradation.

Excessive discharge of toxic dyes is detrimental to ecological system and human health. Therefore, an effective photocatalyst must be designed and developed to degrade dyes from wastewater. Herein, a novel one-dimensional (1D) flower-like recoverable ZnFe2O4/C/MnO2/BiOI magnetic composite photocatalyst was synthesized via electrospinning technique combined with hydrothermal method. The photocatalytic activities of composite photocatalyst were evaluated by degrading methyl orange (MO) and Rhodamine B (RhB) under simulated light irradiation. The efficiency of ZnFe2O4/C/MnO2/BiOI photocatalyst in visible light for 150min reached 91% (MO) and 120min reached 94% (RhB). Moreover, the degradation rate of MO still remained 78% after five cycles. The design of 1D magnetic flower-like composite provided a new strategy for preparing photocatalysts possessing excellent photocatalytic efficiency and cyclic stability.

A robust photocatalyst using silver quantum clusters grafted in titanium dioxide nanotubes

Enhanced photocatalytic activity resulting from the direct electron transfer from noble metal nanoparticles coupled with semiconductor nanostructures is well reported. However, studies on the photocatalytic activity of semiconductor nanostructures coupled with noble metal clusters that exhibit fascinating chemical, optical, and electronic properties are still limited. In this context, we herein report the fabrication of silver quantum clusters grafted on titanium dioxide nanotubes (AgQCs-TNT) towards the photodegradation of ibuprofen and photoreduction of hexavalent chromium ions under visible light irradiation. The structural, chemical, morphological, and optical properties of the as-synthesized samples were studied through X-ray diffraction, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and UV-visible diffuse reflectance spectroscopy. Interestingly, AgQCs-TNT exhibited excellent photocatalytic efficiency in the degradation of ibuprofen and the reduction of hexavalent chromium ions under visible light irradiation in comparison to their pristine counterparts. Role of scavengers and plausible mechanisms pertaining to the improved photocatalytic activity of AgQCs-TNT due to the synergy between the pristine counterparts are discussed.

Synthesis and characterization of a new hybrid nanocomposite based on di-substituted heteropolyanion-quantum dots as a high-performance nanocatalyst for organic dye removal from wastewater

In this manuscript, a new hybrid nanocatalyst (PMo10Ni2/ZnS@CS) based on di-substituted heteropolyanion (PMo10Ni2) and ZnS quantum dot was synthesized via the hydrothermal method. PMo10Ni2/ZnS@CS is a candidate for removal of environmental pollutants. The synthesized hybrid nanocatalyst was analyzed by TEM, UV-vis, FT-IR, XRD, and EDX techniques. The results of XRD analysis showed the average crystallite size of the PMo10Ni2/ZnS@CS nanocomposite particles is about 33 nm, which was consistent with the TEM results. The nano-catalytic activity of PMo10Ni2/ZnS@CS hybrid nanocomposite was investigated in photocatalytic decolorization of organic dyes. The experimental results showed that the inorganic-organic hybrid nanocomposite (PMo10Ni2/ZnS@CS) had excellent photocatalytic efficiency with 98% dye removal. The recovery of the photocatalyst in the decolorization process was investigated and the results indicate a reduction of photocatalytic power after the second and third stage recovery, respectively. In the present study, PMo10Ni2/ZnS@CS was proposed as a heterogeneous nanocatalyst with broad nanocatalytic applications of dye removal.

Precisely engineered type II ZnO-CuS based heterostructure: A visible light driven photocatalyst for efficient mineralization of organic dyes

Herein, type-II band alignment of magnetic ZnO/CuS has been achieved by assembling p-type CuS nanoparticles on n-type ZnO heterostructures to accomplish the photocatalytic degradation of two colored cationic dyes, namely, methylene blue (MB) and toluidine blue (TB). The material exhibited excellent photocatalytic efficiency towards MB and TB with 93% and 87.5% degradation in just 16 and 18 min respectively. The efficacy of doped photocatalyst (FSZCS) was found to be 6 times higher than the undoped material (Fe3O4@SiO2@ZnO; FSZ) whereas pristine CuS degraded only 50% of the dye sample under identical conditions. Therefore, the dramatic enhancement of the photocatalytic degradation performance could be attributed to the synergetic effect created by doping CuS over magnetic ZnO nanocomposites which extended the photoresponse of ZnO by driving the entire degradation process under visible light irradiation and also reducing the charge recombination rate. The plausible mechanistic pathway and identification of degradation products was discussed in detail on the basis of scavenger studies as well as GC–MS analysis. Furthermore, the designed catalyst could be recycled and reused up to 5 runs without any significant decrease in its photocatalytic activity. The reported procedure exhibited multiple advances as it proceeded by utilizing renewable household LEDs as power source at room temperature without the use of any additional oxidant under neutral pH conditions thus, paving a strong path towards sustainable, green and responsible chemistry.

Development of physicochemically stable Z-scheme MIL-88A/g-C3N4 heterojunction photocatalyst with excellent charge transfer for improving acid red 1 dye decomposition efficiency

The MIL-88A/g-C3N4 heterojunction photocatalyst with high physicochemical stability and excellent charge transfer has been successfully developed in this study, and the synergistic effect and the photocatalytic mechanism of the MIL-88A/g-C3N4 composite for Acid Red 1 (AR1) dye decomposition has been discussed in detail. Under simulated-sunlight irradiation, the MIL-88A/g-C3N4 composite showed excellent photocatalytic efficiency for AR1 dye decomposition (100% decomposition efficiency within 30 min for 10 ppm AR1 dye) without the addition of any oxidizing agent, and the composite maintained 97% decomposition efficiency when used repeatedly. The Nyquist plot analysis and the electrochemical analysis results confirm that the improved photo-generated electrons and holes separation and transfer efficiencies of MIL-88A/g-C3N4 could be attributed to the Z-scheme structure formed between MIL-88A and g-C3N4, leading to excellent oxidation efficiency of AR1 dye. The effects of synthesis time of MIL-88A and coupling ratio of MIL-88A on the photocatalytic activity of MIL-88A/g-C3N4 heterojunction composites have been detailed evaluated in this study.

Biomorphic CdS/Cd Photocatalyst Derived from Butterfly Wing for Efficient Hydrogen Evolution Reaction

AbstractPhotocatalytic splitting of water into hydrogen has attracted growing concerns as a promising strategy for the development of clean and renewable energy sources. Fabricating novel photocatalysts with high H2 evolution rate and good cyclic stability is extremely vital for practical applications. Herein, a novel CdS/Cd2SO4(OH)2 composite derived from cadmium nitrate doped Cd‐MOF is deposited on the surface of butterfly wings with reticular hierarchical structure for efficient hydrogen evolution reaction. The combination of unique hierarchical structure and MOF‐derived CdS nanoparticles endows them with strong light absorbability, small band gap, and superior photogenerated charges separation efficiency, leading to excellent photocatalytic efficiency. Furthermore, in‐depth measurements reveal the reduction of Cd2SO4(OH)2 to Cd on the surface of CdS particle during the photocatalytic process. The obtained Cd metal can act as the electron trap to improve the charge separation efficiency and further promote the hydrogen production performance. As a result, the MOF‐derived CdS/Cd2SO4(OH)2 and final CdS/Cd systems with reticular hierarchical structure exhibit significantly enhanced hydrogen production performance compared with CdS/Cd2SO4(OH)2 powder and MOF‐derived CdS nanoparticles under visible light irradiation. It is expected that this synthetic approach can be used to fabricate other composite photocatalyst materials with reticular hierarchical structure for efficient water splitting to hydrogen.

ZIF-8-derived photocatalyst membrane for water decontamination: From static adsorption-degradation to dynamic flow removal

Photocatalysis has been considered a promising method for environmental purification. However, powder nanomaterials are not suitable for large-scale application due to the limit of low recyclability and energy-intensive operation. Integrating and depositing powder photocatalysts on monolithic substrates may solve these issues. In this study, a ZIF-8 photocatalyst membrane and its derived product (ZnS photocatalyst membrane) was constructed by a facile in-situ treatment of cellulose-based substrate (take filter paper as an example). Both the two nanomaterials were confirmed to be tightly anchored to filter paper with the aid of chemical interaction. Under visible light irradiation, excellent dynamic-flow photocatalytic removal efficiencies of methylene blue (MB) degradation (97% within 80 min, k = 0.042 ± 0.002 min−1) and Cr(VI) reduction (100% within 60 min, k = 0.116 ± 0.007 min−1) were achieved by the prepared ZIF-8 photocatalyst membrane and its derived ZnS photocatalyst, respectively. Considering the high MB adsorption capacity and facile regeneration process of ZIF-8 photocatalyst membrane, the adsorption-degradation strategy was promising for its universal applications. The MB degradation pathway and photocatalytic mechanisms were also explored. Ultimately, a comprehensive discussion on the advantages and implications of prepared photocatalyst membranes for photocatalytic water treatment was rationally proposed. This study provided a promising method for water decontamination and demonstrated the significant superiority of monolithic membrane for photocatalytic water treatment.

One-step synthesis of S-doped and nitrogen-defects co-modified mesoporous g-C3N4 with excellent photocatalytic hydrogen production efficiency and degradation ability

S-doped and nitrogen defect co-modified mesoporous g-C3N4 (Tm-g-C3N4) is successfully prepared. Introduced mesopores result in an expansion of the surface area to 153.8 m2 g-1 which provides more active sites. S-doped and nitrogen defect co-optimize band structure, decrease the band gap energy and expand the light absorption capacity, simultaneously new excessive conduction band energy level is generated, which could accept more photogenerated electrons, promoting separation and migration of photo-generated carriers. Hence, its H2 evolution rate is 4441 μmol g-1 h-1, which is 48.8 folds more than previous one. Meanwhile, there is also a superior function in degradation (RhB, MO, MB, TC and CV), and keeps an excellent stability. Clearly, this work uses multiple modification methods for obtaining an efficient photocatalyst, which might exhibit marvelous effect on the fields of environmental treatment and energy development.

Construction of mesoporous lanthanum orthovanadate/carbon nitride heterojunction photocatalyst for the mineralization of trichloroethylene

The search for stable, high-performance, and low-cost photocatalysts has received considerable interest. In this work, mesoporous LaVO4 nanoparticles were synthesized for the first time by applying the soft template, and g-C3N4 nanosheets were fabricated using a hard template to design mesoporous LaVO4/g-C3N4 heterostructures. The synthesized photocatalysts were assessed by the mineralization of trichloroethylene (TCE) in aqueous media during visible illumination. TEM and XRD measurements verified the existence of porous g-C3N4 with a high distribution of the monoclinic phase LaVO4 NPs (5 nm). The photocatalytic performance of the LaVO4/g-C3N4 heterojunction was much better than that of either LaVO4 or g-C3N4. 3%LaVO4/g-C3N4 exhibited the maximum photocatalytic ability, about 99% during a 3 h illumination at a degradation rate of 6.50 μmolL−1 min−1, which were ∼3.89- and ∼4.67-fold greater than parent LaVO4 and g-C3N4, respectively. The first-order kinetics calculations revealed that the 3% LaVO4/g-C3N4 heterostructure offered the highest rate constant of 0.0113 min−1, which estimated ∼8.7 and 4.9 folds larger than LaVO4 (0.0023 min−1) and g-C3N4 (0.0015 min−1), respectively. The importance of the LaVO4/g-C3N4 with superb photocatalytic efficiency was demonstrated based on the photoluminescence spectra, transient photocurrent curves, and UV–visible absorption spectra. The obtained LaVO4/g-C3N4 photocatalyst exhibited excellent regeneration and recyclability over five consecutive runs. The coupling of LaVO4 and g-C3N4 with matching alignment potentials and the synergetic effect were thought to be the most interesting processes to promote photocatalytic efficiency. The obtained LaVO4/g-C3N4 heterojunction possesses excellent photocatalytic efficiency and is a favorable candidate for potential applications in wastewater remediation using solar energy.