Excellent Photocatalytic Activity Research Articles

Visible Light-Assisted Degradation of Sulfamethoxazole on 2D/0D Sulfur-Doped Bi2O3/MnO2 Z-Scheme Heterojunction Immobilized Photocatalysts.

Retrieving the spent photocatalysts from the reaction system is always a challenging task. Therefore, the present work is focused on immobilizing sulfur-doped-Bi2O3/MnO2 (S-BOMO) heterojunction photocatalysts over different support matrices and evaluating their performance for the removal of sulfamethoxazole (SMX) in water under visible light. Our findings revealed S-BOMO coated clay beads (S-BOMO CCB) achieving more than 86% (240 min) SMX degradation ∼3, ∼1.3, and ∼2 times higher compared to S-BOMO coated on the different substrates, including glass beads, floating stones, and polymer material substrates, respectively. Mott-Schottky measurements confirmed the construction of the Z-scheme heterojunction involving MnO2 and 2S-Bi2O3. This Z-scheme mechanism, along with its narrow band gap of 1.58 eV, resulted in a rapid spatial transfer of the photogenerated charge carriers between the semiconductors and is believed to enhance the overall photocatalytic activity of the nanocomposite. Radical trapping and electron paramagnetic resonance results clearly established the active role of hydroxyl radicals and hydrogen peroxide in the degradation of SMX. Further, the 2S-BOMO CCB demonstrated excellent stability and photocatalytic activity over multiple runs. According to the sensitivity analysis and the results of anion effect experiments, phosphate and sulfate ions exhibit a significant impact on sulfamethoxazole degradation. Toxicity analysis revealed that 2S-BOMO CCB and sulfamethoxazole degradation byproducts were apparently innocuous. Additionally, the practical applicability of 2S-BOMO CCB was examined in various real water matrices, with the degradation efficiency followed the order: tap water < groundwater < surface water < hospital wastewater < municipal wastewater < pharmaceutical industry wastewater. The economic assessment revealed the reduction in the overall cost of the immobilized 2S-BOMO following the recovery process. Overall, the findings of this work provided critical insights into the synthesis and performance of incredibly effective and stable immobilized photocatalysts for the degradation of pharmaceutical pollutants.

Fast and facile pH tailored green synthesized ZnO photocatalyst by biogenic reduction using water extract of Averrhoa bilimbi (L) fruit

Abstract The present study reports an economical and environmentally friendly technique for the synthesis of zinc oxide nanoparticles. The water extract of Averrhoa bilimbi (L) fruit was used in this one-pot synthesis approach for ZnO nanoparticle reduction and stabilisation. Varied size, shape and properties of the synthesized nanomaterials were obtained by tuning the pH of the synthesis medium. X-ray diffraction techniques, diffuse reflectance spectroscopy, photoluminescence and scanning electron microscopy analysis were used for characterizing phytochemical capped ZnO nanoparticles. The morphological change with varying pH was observed from scanning electron microscopy images. Short duration of synthesis with high yield product at ambient room temperature are the salient features of this procedure. The synthesised ZnO nanoparticles showed excellent photocatalytic activity and superhydrophilicity to be used in a wide range of applications.

Photocatalytic water splitting properties of GeC/InS van der Waals heterostructure: first-principles calculations

Based on first-principles, we conducted an in-depth study of the GeC/InS van der Waals heterostructure formed by GeC and InS and discussed its structure, electronic properties and optical properties. First, we observe that this heterostructure has negative binding energy, indicating that the interlayer interactions are mainly affected by van der Waals forces. Through band structure and density of state analysis, we confirmed its type-II band alignment characteristics, which means that photogenerated carriers have the ability to automatically separate in space. Moreover, the average charge density difference and Bader charge analysis show that there is a built-in electric field in the heterostructure, and further proves that GeC/InS forms a Z-scheme charge transfer mechanism. Interestingly, the band edge position spans the water redox potential and can fully induce the redox reaction of water splitting, indicating that it is a potential photocatalyst. The high light absorption coefficient shown in the absorption spectrum also further confirms its excellent photocatalytic activity. The most striking thing is that the solar hydrogen production efficiency of GeC/InS heterostructure is as high as 44.39%. Our research demonstrates the theoretical basis for GeC/InS heterostructure as a photocatalyst.

Design and fabrication of g-C3N4/Bi2S3 heterojunction photocatalysts for efficient organic pollutant degradation and antibacterial activity

Developing highly effective photocatalysts is essential in environmental remediation and sustainable manufacturing. In this study, a carbon-based semiconductor nanocomposite (g-C3N4/Bi2S3) was effectively prepared via a hydrothermal approach. Comprehensive physicochemical characterizations were active to assess the morphological, structural, and photochemical attributes of the fabricated g-C3N4/Bi2S3 nanocomposites using microscopic and spectrophotometric analyses while the intermediate products formation was assessed through GC-MS analysis. Photocatalytic degradation performance was evaluated against Reactive Black 5 (RB5) and Indigo Carmine (IC) dyes. The g-C3N4/Bi2S3 nanocomposites exhibited remarkable photodegradation efficiency compared with pure g-C3N4 and Bi2S3 catalysts, achieving 95.6 % degradation for IC and 97.5 % for RB5 after 120 min of Ultraviolet A irradiation (UVA). This excellent photocatalytic activity demonstrates the potential of g-C3N4/Bi2S3 nanocomposites for future employment in visible-light-driven wastewater treatment. The mechanism of g-C3N4/Bi2S3 NCs photocatalysis involves efficient charge separation, active site interactions, electron and hole transfer, and subsequent oxidative removal of organic pollutants, revealing the NCs suitability for sustainable environmental applications. Furthermore, the effectiveness of the g-C3N4/Bi2S3 nanocomposites in combating Streptococcus mutans and Enterococcus faecalis was appraised under UVA light exposure to determine their antibacterial properties.

Interfacial engineering of 0D/2D Cd0.5Zn0.5S/Ti3C2 for efficient photocatalytic synergistic removal of antibiotics and Cr(VI)

The pollution of antibiotics and heavy metals in water environment is considered to be an urgent environmental problem. However, designing a photocatalyst that can simultaneously remove these contaminants remains a challenge. 0D/2D Cd0.5Zn0.5S/Ti3C2 (CZSMX) hybrids were fabricated by uniformly coating Cd0.5Zn0.5S (CZS) nanospheres on the surface of Ti3C2 nanosheets. The removal efficiency of the suitable CZSMX hybrid on tetracycline hydrochloride (100 mg/L), 7-amino-cephalosporin (100 mg/L), and Cr(VI) (50 mg/L) is 92%, 97%, and 72%, respectively. Meanwhile, it still exhibits excellent photocatalytic removal activity in the mixed contaminants solution. Additionally, CZSMX-3 exhibits outstanding physical and chemical stability after 5 cycles. Importantly, the enhanced photocatalytic activity of CZSMX is attributed to the accelerated charge carrier separation due to the excellent electrochemical and photochemical properties of Ti3C2. Overall, this study provides a strategy for the efficient collaborative removal of antibiotics and heavy metal from wastewater by photocatalysis of metal sulfide based photocatalysts.

Ag3PO4/g-C3N4/Zn3(PO4)2 catalyst with ternary heterostructure and Z-scheme/type Ⅱ dual pathway mechanism for high photocatalytic performance

A novel Ag3PO4/g-C3N4/Zn3(PO4)2 photocatalyst with ternary heterostructure and Z-scheme/type Ⅱ dual pathway mechanism was synthesized. Scanning electron microscopy and transmission electron microscopy data showed that Ag3PO4, Zn3(PO4)2, and g-C3N4 were in close contact, leading to the formation of the ternary heterojunction. Under simulated solar light irradiation, the Ag3PO4/g-C3N4/Zn3(PO4)2 photocatalyst efficiently degraded rhodamine B (RhB) and displayed much higher photocatalytic activity than pure Ag3PO4, g-C3N4, Zn3(PO4)2, and Ag3PO4/Zn3(PO4)2 composite, exhibiting a RhB photodegradation efficiency of ∼91.2 % within 60 min. The quenching effects of different scavengers and electron spin resonance (ESR) experiments demonstrated that reactive h+ and·O2− species played major roles in the photocatalytic reaction. It was elucidated that excellent photocatalytic activity could be ascribed to the Z-scheme/type Ⅱ dual carrier transfer pathways. Therefore, the formation of a ternary heterostructure system is an efficient method for separating charge carriers and retaining their redox capabilities.

Noble metal-free 0D-1D CoOx/Mn0.3Cd0.7S nanocomposites for efficient visible-light hydrogen production

Here, a series of MnxCd1-xS sosoloid composite photocatalysts with visible-light activity were first prepared by a solvothermal process. The element ratio of Cd2+ to Mn2+ was optimized to be Mn0.3Cd0.7S in MnxCd1-xS sosoloid on account of its photocatalytic activity for H2 evolution from H2O in response to visible light excitation. And on this basis, the CoOx nanopariticles were loaded on the surface of Mn0.3Cd0.7S sosoloid composite to obtain a binary p-n heterojunction of CoOx/Mn0.3Cd0.7S composite through a facile impregnation process and a high temperature sintering procedure. Benefitting from the synergistic effect of the built-in electric field, binary p-n heterojunction structure, and rearrange of the Fermi level equilibrium, the as-synthesized CoOx/Mn0.3Cd0.7S composite presents a highly enhanced photocatalytic activity for hydrogen production from H2O in response to visible light excitation, which is demonstrated to be 53.4 and 4.0 times higher than that of the primitive CdS and Mn0.3Cd0.7S, respectively. Furthermore, after 4 times circles of photocatalytic H2 production tests, the CoOx/Mn0.3Cd0.7S composite still keeps 92.0 % of the original photocatalytic activity. Considering its reasonable photochemistry stability and excellent photocatalytic activity for hydrogen evolution from H2O under with visible light excitation, the as-synthesized CoOx/Mn0.3Cd0.7S composite has potential applications in solar hydrogen production areas.

Bi3+ doping-enhanced optical and photocatalytic activity with stability of cobalt nickel zinc ferrites for wastewater treatment applications

In this paper, the spinel ferrite nanoparticles Co0.5Ni0.25Zn0.25BixFe2−xO4 (CNZBF) were prepared by citrate-nitrate auto combustion method. Although the substitution process involves a large ion at the expense of a small one, the lattice constant didn't introduce a regular increment behavior with irregular shifts for the peak position at 34.62°, which is related to the (311) plane. Two hypotheses were introduced to justify this behavior. The crystallite size introduced a peculiar behavior in the span of 20.88–14.78 nm with increasing the Bi3+ content. Morphological study via FE-SEM manifested that the CNZBF nanoferrites have agglomerated spherical shapes. Kubelka-Munk function and Tauc's plot for direct allowed transitions were utilized to determine the band gap of all the CNZBF nanoferrites. The doping of Bi tuned the band gap (within 1.55 to 1.25 eV), boosted the light absorption, induced efficient e/h separation, and ensuing charge migration to the Co0.5Ni0.25Zn0.25BixFe2−xO4 surfaces. On account of the CNZBF advantages, a superb removal efficiency (∼96.41 %) of the sample Co0.5Ni0.25Zn0.25Bi0.08Fe1.92O4 via photocatalytic degradation was achieved. After five reusability cycles the nanocatalyst Co0.5Ni0.25Zn0.25Bi0.08Fe1.92O4 introduced 95.08% degradation which demonstrates a trivial efficiency decline of 1.33 % in the photocatalytic activities. These outcomes of excellent photocatalytic activity with the outstanding stability candidate the novel Co0.5Ni0.25Zn0.25Bi0.08Fe1.92O4 for wastewater treatment applications.

Controllable construction of direct Z-scheme Mo2C-CdxZn1−xIn2S4 heterojunction via defect-mediated modulation for enhanced visible-light photocatalysis

Direct Z-scheme semiconductor heterostructures possess fascinating merits for solar photocatalysis, including increased light harvesting, spatially isolated photogenerated charge carriers, and well-preserved strong redox capability. However, steering Z-scheme charge transfer of semiconductor heterojunction in a controllable manner is still a challenging task. In this work, unique direct Z-scheme Mo2C-CdxZn1−xIn2S4 heterojunction is constructed via a defect-mediated modulating strategy, where Cd-doping switches the charge transfer mode of Mo2C-CdxZn1−xIn2S4 heterojunction from type-I to Z-scheme through increasing S vacancies, up-shifting conduction band level, and narrowing bandgap of CdxZn1−xIn2S4 component. Moreover, the defect-induced Mo-S bond affords fast channels for built-in electric field-induced Z-scheme photo-electrons transporting from Mo2C conduction band to CdxZn1−xIn2S4 valence band, supporting by X-ray photoelectron spectroscopy, surface photovoltage spectroscopy, and radical testing results. Noticeably, under irradiation of visible light (λ > 400 nm), Mo2C-CdxZn1−xIn2S4 Z-scheme heterojunction displays an excellent and stable photocatalytic H2-evolving activity, reaching an outstanding H2 generation rate of 28.12 mmol·g−1·h−1 with the corresponding high apparent quantum efficiency of 21.1% at 400 nm, far surpassing that of Pt-loaded C0.25ZIS and most documented ZnIn2S4-containing photocatalysts. The present work could inspire the crafty design of efficient Z-scheme photocatalysts through defect-mediated heterostructure construction and energy band engineering.

Modulating the microenvironment of catalytic interface with functional groups for efficient photocatalytic degradation of persistent organic pollutants

The solar-driven photocatalytic degradation of persistent organic pollutants is considered as a promising water treatment approach.Nevertheless, the activity of photocatalytic degradation of pollutants is still limited by the rapid carrier recombination and sluggish oxygen mass transfer. Herein, we designed different functional groups modified WO3/R-MOF (MOF: MIL-125-Ti, R = NH2, C5H11, C5F11) heterojunction to overcome the aforementioned limitations. Among them, WO3/C5F11-MOF exhibited an excellent degradation efficiency of 91.6 % for 4-chlorophenol pollutants, which was seven and two times higher than that of WO3/NH2-MOF and WO3/C5H11-MOF, respectively. The WO3/C5H11-MOF and WO3/C5F11-MOF exhibited hydrophobic and formed microscopic triphase interface, which increased oxygen transfer. Furthermore, strong electron-withdrawing property of fluorine in the C5F11- ligand generated electron-deficient regions, increasing the transfer rate of photo-generated electrons and prolonging the relaxation time of electrons. Thus, hydrophobic WO3/C5F11-MOF not only regulates the catalytic interface microenvironment, but also effectively inhibits the recombination of photo-generated carrier. This study provides an efficient strategy to achieve excellent photocatalytic activity via interfacial engineering.

Study of Bi-functional Applications of ZnO Nanoparticles Synthesized via Sonochemical Route

The sonochemical synthesis involved the dispersion of zinc oxide (ZnO) precursor in a suitable solvent, followed by ultrasonic irradiation to induce chemical reactions and nucleation of ZnO nanoparticles. The resulting nanomaterials exhibited a uniform particle size distribution, which is crucial for their photocatalytic efficiency. ZnO nanoparticles with a uniform particle size of 25 nm were successfully synthesized using a sonochemical route and were employed for the degradation of direct green and fast orange dyes under UV light irradiation. The band gap of the ZnO nanoparticles was determined to be 3.35 eV, indicating its potential as a photocatalyst for dye degradation. The degradation efficiency of the dyes was evaluated by monitoring the change in their concentration over time. The ZnO nanoparticles demonstrated excellent photocatalytic activity, efficiently degrading both dyes within a relatively short duration. The electrochemical studies further confirmed the potential applicability of the synthesized ZnO nanoparticles in various electrochemical systems. The ZnO electrode that was produced could detect lead in an acidic solution. The ZnO electrode is a promising electrode material for making sensor applications because of its higher electrochemical behaviour. Overall, this research contributes to the development of efficient and environmentally friendly approaches for wastewater treatment and lead sensor.

Facile construction of BiOI/Nb2O5 heterojunction films and their excellent photocatalytic activity

Facile construction of BiOI/Nb2O5 heterojunction films and their excellent photocatalytic activity

Tuning the Aggregates of Thiophene‐based Trimers by Methyl Side‐chain Engineering for Photocatalytic Hydrogen Evolution

AbstractOrganic π‐conjugated semiconductors (OCSs) have recently emerged as a promising alternative to traditional inorganic materials for photocatalysis. However, the aggregation of OCSs in photocatalytic aqueous solution caused by self‐assembly, which closely relates to the photocatalytic activity, has not yet been studied. Here, the relationship between the aggregation of 4,7‐Bis(thiophen‐2‐yl) benzothiadiazole (TBT) and the photocatalytic activity was systematically investigated by introducing and varying the position of methyl side chains on the two peripheral thiophene units. Experimental and theoretical results indicated that the introduction of ‐CH3 group at the 3‐position of TBT resulted in the smallest size and best crystallinity of aggregates compared to that of TBT, 4‐ and 5‐positions. As a result, TBT‐3 exhibited an excellent photocatalytic activity towards H2 evolution, ascribed to the shorten charge carrier transport distance and solid long‐range order. These results suggest the important role of aggregation behavior of OCSs for efficient photocatalysis.

Effect of annealing temperature on the formation of oxygen vacancies on the surface of flower-like SnSe/SnO2 heterostructure and visible light catalytic performance

The morphology, structure, and oxygen vacancies in principle determine the light absorption, charge transfer, and separation of photocatalysts, thereby determining their photocatalytic performance. In this study, flower-like SnSe obtained from hydrothermal reactions was oxidized to obtain heterojunctions with SnSe/SnO2. Flower-like SnSe/SnO2 heterojunctions with different concentrations of oxygen vacancies were prepared by annealing them in an argon atmosphere at different temperatures. The flower-like SnSe/SnO2 series with different oxygen vacancies were systematically characterized by TEM, XRD, XPS, PL, and EPR. The research results demonstrate the presence of oxygen vacancies in the flower-like SnSe/SnO2. As the annealing temperature increases, the surface oxygen vacancy concentration shows a trend of first increasing and then decreasing. When the annealing temperature reaches 600 °C, the oxygen vacancy concentration of flower-like SnSe/SnO2 is the highest. Meanwhile, research has shown that surface oxygen vacancies help expand the light absorption range, and the increased valence bandwidth leads to effective charge transfer and separation, thereby promoting visible light photoactivity. SnSe/SnO2-600 °C exhibited excellent visible light photocatalytic activity. The photodegradation of methylene blue (MB) at ≥ 400 nm can reach ∼70% within 120 min. This study verified the route for the introduction of oxygen vacancies via facile calcination and constructed SnSe/SnO2 with surface oxygen vacancies, providing a reference with deep insights for improving photocatalytic activity.

Ni Nanoparticles Supported Over Triazine Based Porous Organic Polymer for Selective CO2 Photo‐Reduction to Methanol

AbstractPorous organic polymers (POPs) have attracted substantial attentions over the years due to their exceptionally high specific surface areas, high chemical stability of the organic network and ease of surface functionalization with the desired organic groups. In this work, a triazine based POP (TrzPOP) was synthesized through Schiff base polycondensation reaction between a tetramine bearing triazine rings and phenolic–OH group rich dialdehyde. Ni nanoparticles (NiNP) synthesized independently were immobilized over TrzPOP to obtain the NiNP@TrzPOP composite catalyst. This TrzPOP possesses a high BET surface area of 1494 m2 g−1 and low band gap, which facilitates its role as visible light absorbent. NiNP@TrzPOP with N‐rich surfaces and phenolic–OH moieties displayed excellent photocatalytic activity in the CO2 photoreduction under mild reaction conditions. NiNP@TrzPOP composite selectively reduces CO2 to methanol. The turn over number (TON) for this photoreduction of CO2 under optimized reaction conditions is 270, which is considerably high comparing to other reported photocatalytic systems. Moreover, NiNP@TrzPOP composite catalytic system showed high recycling efficiency without noticeable decrease in its performance over five consecutive reaction cycles, suggesting its huge potential for large‐scale methanol synthesis from the renewable carbon source.

Pt nanoclusters modified porous g-C3N4 nanosheets to significantly enhance hydrogen production by photocatalytic water reforming of methanol

For the use of green hydrogen energy, it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions. Much attention has been paid to g-C3N4 as a promising photocatalyst for the generation of hydrogen. To improve the separation of photogenerated charge, porous nanosheet g-C3N4 was modified with Pt nanoclusters (Pt/g-C3N4) through impregnation and following photo-induced reduction. This catalyst showed excellent photocatalytic activity of water reforming of methanol for hydrogen production with a 17.12 mmol·g−1·h−1 rate at room temperature, which was 311 times higher than that of the unmodified g-C3N4. The strong interactions of Pt–N in Pt/g-C3N4 constructed effective electron transfer channels to promote the separation of photo-generated electrons and holes effectively. In addition, in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction, which proved that methanol and water eventually turn into H2 and CO2via formaldehyde and formate. This study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.

Remarkably enhanced hydrogen evolution of g-C3N4 nanosheet under simulated sunlight via AgPt alloy co-catalyst with low amount of Pt

The development of low-cost co-catalysts matched with proper photocatalysts to enhance the photocatalytic hydrogen evolution performance is highly demanded. Herein, the AgPt bimetallic alloy nanoparticles with small amounts of Pt were decorated on g-C3N4 nanosheets (AP-CN) via the NaBH4 reduction method, which were further used as catalysts towards photocatalytic hydrogen evolution from water under AM1.5 irradiation. Compared to mono-metallic co-catalysts, bimetallic AgPt alloy nanoparticles exhibited excellent co-catalytic performance. The optimum AP-CN photocatalyst with 0.5 wt% Pt exhibited photocatalytic hydrogen evolution rate of 3507.89 μmol g−1·h−1, which even surpassed that of the commonly-used photocatalyst 1.0 wt% Pt in-situ photo-deposited on g-C3N4. Meanwhile, the AP-CN showed excellent photocatalytic activity and durability after four experimental cycles. The enhanced activity and stability could be attributed to the synergistic effect between plasmonic metal Ag and Pt, which promoted the transfer and separation of photoinduced charge carriers. Besides, the theoretical results based on DFT calculation also verified that AgPt alloys have better performance of desorbing hydrogen and adsorbing H atoms. This work provides a feasible idea for the development of inexpensive and efficient bimetallic co-catalysts for photocatalytic hydrogen production through water splitting.

Synthesis of S-type heterostructure π-COF for photocatalytic tetracycline degradation

Photocatalytic oxidation is a promising technology for wastewater treatment. It is a more desirable method than other conventional wastewater treatment approaches due to its low cost, environmental friendly, and capability to completely degrade pollutants into environmentally safe products under appropriate conditions. Among some photocatalysts, covalent organic frameworks with high photoactivity are recognized as stable and feasible materials for this purpose. In this work, highly-effective photocatalyst of S-type heterostructure π-COF was successfully synthesized by using ultrasonic delamination treatment sp2c-COF nanosheets (sp2c-NS) and py-NH2-COF nanosheets (Py-NH2-NS) via a secondary solvent heating method. The preparation was initiated by synthesizing sp2c-COF and py-NH2-COF successfully adopting pyrene templates by solvothermal method. The study focused on physicochemical characterization and photocatalytic activity of π-COF. The photocatalytic ability of π-COF was carried out to degrade tetracycline under visible light. The results indicate that π-COF not only shows excellent photocatalytic activity for tetracycline degradation of 94.8 % at 90 min under visible light illumination, but also has good photocatalytic degradation performance at wide initial pH values, coexisting ions, and actual water sources. Surprisingly, it has excellent stability and recyclability, it can afford high oxidative degradation (87.3 %) even after 5 successive recycles. The degradation mechanism was discussed by various methods such as active species trapping experiment, electron paramagnetic resonance determination and related electrochemical analysis. In addition, the main degradation intermediate products and the possible pathways of TC degradation were detected and proposed according to LC − MS technology. This work provided a new strategy for the preparation of hetero-structured COF which could be served as an advantageous photocatalyst for the treatment of pharmaceutical industry wastewater.

One-Dimensional Shaving-like BiVO4 Nanobelts: Synthesis, Characterization and Photocatalytic Activity with Methylene Blue

One-dimensional shaving-like BiVO4 nanobelts were successfully synthesized via the oxide hydrothermal method (OHS), using V2O5 and Bi2O3 as raw materials and PEG 10000 (polyethylene glycol 10000) as a template. Multiple techniques, including XRD, SEM, TEM, HRTEM, UV–Vis, XPS, and photoelectrochemical measurements, were applied to characterize the obtained materials. The thickness of the BiVO4 nanobelt was approximately 10 nm, while the width was approximately 500 nm. EIS results showed that visible-light illumination caused the photogenerated charge of the BiVO4 nanobelts to have a faster transfer and a higher separation efficiency. Photocatalytic experiments indicated that with BiVO4 nanobelts as a catalyst, the degradation rate of MB (methylene blue) was close to 92.4%, and it disintegrated after two hours. Moreover, the pseudo-first-order kinetic model can be used to describe the photodecomposition reaction of MB catalysed by BiVO4 nanobelts. And this excellent photocatalytic activity of the shaving-like BiVO4 nanobelts may be related to their special morphology, narrow band gap (~2.19 eV), faster transfer and the separation efficiency of the photogenerated charge, leading to strong absorption in the visible region and improving the separation of the photogenerated electron–hole pairs. These novel monoclinic BiVO4 nanobelts exhibited great photocatalytic activity and are thus a promising candidate for application in visible-light-responsive photocatalysts.

Facile synthesis of silver chloride-polyaniline nanocomposites and its photocatalytic activity for the degradation of methylene blue

Herein, we report a green and an effective strategy for the synthesis of polyaniline-silver chloride (AgCl@PANI) nanocomposites by using facile in-situ chemical oxidative polymerization method in the presence of as-synthesized silver nanoparticles (Ag NPs) for the study of their photocatalytic activity towards the photodegradation of methylene blue (MB) under UV irradiation. The contents of Ag NPs varied from 2% to 6% during polymerization reaction to get AgCl@PANI nanocomposites. These synthesized polymer nanocomposites were characterized for their structural and optical properties, thermal stability, dc conductivity and photocatalytic activity by FT-IR spectroscopy, XRD, UV–Vis spectroscopy, TGA, SEM, standard four probe method and the photodegradation activity of MB, respectively. XRD analysis confirm the successful formation of AgCl@PANI nanocomposites without the presence of additional phases. TGA shows that AgCl@PANI nanocomposites have excellent thermal stability due to the barrier effect of AgCl moieties bounded with in the polymer chain and the strong physiochemical interactions between PANI and AgCl as inferred from FT-IR and UV–vis analysis. Under UV irradiation, the AgCl@PANI nanocomposite, with 4 wt% of Ag NPs (AgCl@PANI-4%), demonstrated excellent photocatalytic activity for MB degradation with the photodegradation percentage of ∼ 99 % in 20 min. The experimental findings illustrate that the superior photocatalytic activity of AgCl@PANI nanocomposites is owing to incorporation of AgCl moieties in the polymer structure, less needed energy for the formation of electron-hole pairs in the quinoid ring of PANI in the UV-region, enhanced light absorption owing to smaller grain size morphology, high surface area of the nanocomposite and high electrical conductivity (128 mS.cm−2). These results suggest the potential of these synthesized conjugated polymer-based nanocomposites as a photocatalyst for cost-effective and efficient wastewater treatment for the industrial applications.