Fabrication of novel AgVO3/BiOI nanocomposite photocatalyst with photoelectrochemical activity towards the degradation of Rhodamine B under visible light irradiation

Engineered oxygen vacancies in NiCo2O4/BiOI heterostructures for enhanced photocatalytic pollutant degradation

To address the bottleneck issue of poor carrier separation and transfer efficiency in NiCo2O4 photocatalyst, a novel 1D/2D-rod-on-rose-like NiCO2O4/BiOI nanohybrid with abundant OV's was successfully synthesized using a single-step hydrothermal method and employed to the photocatalytic degradation of Rhodamine B (RhB). The study revealed that the optimized NiCo2O4-OV/BiOI hybrid could possess superior photocatalytic degradation efficiency towards RhB degradation under visible light with a rate constant that was 3.8 and 3.03 times greater than that of BiOI and NiCo2O4-OV. Experimental findings indicated that the formation of NiCo2CO4-OV/BiOI heterojunction significantly improved the charge separation efficiency and facilitated the formation of surface OV's. These OVs enhanced photogenerated e--h+ separation and increased catalytic efficiency. Quenching experiments results confirmed that both holes and superoxide radicals are playing crucial roles in the degradation process. Thus, an oxygen vacancy and engineering NiCo2CO4-OV/BiOI heterojunction-enhanced degradation mechanism was proposed, offering insights for the integration of advanced oxidation technologies and the development of catalytic materials to enhance pollutant degradation efficiency.

Free-Standing Nanocomposite Au@Graphene Oxide Continuous Flow Synthesis in Water for Degradation of Organic Dyes

We have developed a rapid and facile method for preparing free-standing nanocomposite of gold nanoparticles with graphene oxide (Au@GO) in water under continuous flow in the absence of harsh reducing agents and any other auxiliary substances, as a method with favourable green chemistry metrics. This uses a vortex fluidic device (VFD) where induced mechanical energy and photo-contact electrification associated with the dynamic thin film in the rapidly rotating tube tilted at 45° while simultaneously UV irradiated (λ=254 nm, 20 W) results in decomposition of water to hydrogen and hydrogen peroxide with growth of the gold nanoparticles on the surface of the GO. We have established that the resulting Au@GO composite sheets rapidly catalyse the degradation of commercial dyes like methyl orange (MO) and methylene blue (MB) using the hydrogen peroxide generated in situ in the VFD. This process relies on active radicals generated through liquid-solid photo-contact electrification of water in the VFD which dramatically minimises the generation of waste in industrial applications, with the reaction having implications for wastewater treatment.

An ultra-sensitive photoelectrochemical biosensing platform based on the AgVO3/BiOI heterojunction for an enzyme activity inhibition reaction

An ultra-sensitive photoelectrochemical sensing platform for profenofos detection based on the inhibition of catalase activity was prepared in this work. First, the novel functional nanocomposite material AgVO3/BiOI was prepared by a hot solvent method and successive ion layer adsorption reaction. Then, chitosan was employed as a dispersion medium to disperse and immobilize the catalase. Under visible light irradiation, the prepared CAT/CS/AgVO3/BiOI/ITO nanocomposite electrode generates a stable low photocurrent in hydrogen peroxide solution. When this electrode is immersed in a phosphate buffer solution containing profenofos, the activity of the catalase is inhibited, resulting in an increase in the photocurrent. Under the optimized experimental conditions, the profenofos concentration and increase in photocurrent are linearly related in the concentration range of 1 × 10-10 to 5.0 × 10-8 mol L-1, and the limit of detection is 1.0 × 10-11 mol L-1. This biosensor shows good selectivity for detecting profenofos in fruits and vegetables, and the determination results of profenofos are satisfactory.

Construction of a novel S-scheme AgVO3/CaIn2S4 heterostructure for efficient photodegradation of tetracycline hydrochloride

Constructing an S-scheme system with highly active catalysts is a significant approach for improving the separation of photoinduced carriers to solve the related environmental aggravation. In this study, a well-designed S-scheme AgVO3/CaIn2S4 photocatalyst was synthesized for water purification by in situ growing CaIn2S4 nanocrystals on AgVO3 nanorod surfaces. The optimized AgVO3/CaIn2S4 heterostructure demonstrates an enhanced photocatalytic efficiency (94.1%) toward tetracycline hydrochloride (TCH) degradation compared with bare AgVO3 (42.6%) and CaIn2S4 (81.6%). The significant enhancement of photocatalytic activity is attributed to the S-scheme charge transfer mechanism in the AgVO3/CaIn2S4 heterostructure, which effectively directs photogenerated charge migration, boosts charge transfer, and preserves the high redox capacity of photoexcited electrons and holes on different active sites. This study is expected to offer insights into strategically designing and preparing S-scheme heterojunction photocatalysts to improve water purification.

Integration of high visible-light-driven ternary dual Z-scheme AgVO3-InVO4/g-C3N4 heterojunction nanocomposite for enhanced uranium(VI) photoreduction separation

With deepening application of nuclear power technology, the problem of water ecological environment pollution caused by uranium (U(VI)) is becoming increasingly serious. Photoreduction separation of U(VI) on photocatalysts is considered as an effective strategy to solve uranium pollution. In this work, a novel ternary dual Z-scheme AgVO3-InVO4/g-C3N4 heterojunction (Z-AIGH) nanocomposite with high surface area (73.45 m2 g-1, Z-AIGH2) was designed. The batch adsorption experiment in dark environment showed that Z-AIGH2 nanocomposite had an excellent U(VI) adsorption performance. As for photocatalytic experiments, Z-AIGH2 exhibited a rapid photocatalytic response for separating U(VI) without any organic sacrifice agents. The U(VI) separation rate on Z-AIGH2 nanocomposite was over 98.7% after only 20.0 min visible light irradiation (T = 298 K, CU(Ⅵ) = 10.0 mg L-1, m/V = 0.1 g L-1 and pH = 7.0). Z-AIGH2 nanocomposite also showed good selectivity and cycle stability. The U(VI) removal rate of Z-AIGH2 nanocomposite after fifth cycles was about 96.1% (T = 298 K, CU(Ⅵ) = 10.0 mg L-1, m/V = 0.1 g L-1 and pH = 7.0). High photocatalytic activity of Z-AIGH2 for U(VI) was attributed to the construction of ternary dual Z-scheme heterojunction structure and ant nest-like hole structure. Based on above results, Z-AIGH2 nanocomposite had great potential for water environment renovation.

A novel magnetic AgVO3/rGO/CuFe2O4 hybrid catalyst for efficient hydrogen evolution and photocatalytic degradation

A superior semiconductor material with efficient charge separation and easy reuse could be a promising route for efficient photocatalytic hydrogen evolution and pollutant degradation. AgVO₃ is one of the best visible light active materials which has attracted much attention for several biological and environmental applications. In the aim of enhancing its stability and recyclability a novel AgVO₃/rGO/CuFe₂O₄ heterojunction was prepared by hydrothermal method for hydrogen generation (H₂) and 4-nitrophenol (4-NP) degradation as well. The composite was well characterized by XRD, SEM, HR-TEM, XPS and VSM. The morphological images suggested the rod shaped AgVO₃ and irregular shaped CuFe₂O₄ are unevenly distributed on reduced graphene oxide (rGO) layers. The hydrogen evolution results indicated that the composite showed around 8.937 mmol g^-1h^-1 of H₂ generation which was ∼2.3 times and ∼9.2 times higher than pure AgVO₃ (3.895 mmol g^-1h^-1) and CuFe₂O₄ (0.96 mmol g^-1h^-1) respectively. The 4-NP degradation efficiency of the prepared composite was observed as 94.7% (k = 0.01841 min^-1) which is much higher than the AgVO₃ (66.3%) and CuFe₂O₄ (38.2%) after 4 h of irradiation. The higher efficiency could be attributed to the heterojunction formation and faster charge separation. The radical trapping results indicated that the •OH, O₂•- and photogenerated h⁺ are the main species responsible for efficient activity. The AgVO₃/rGO/CuFe₂O₄ heterojunction showed 49.6 emu/g of saturation magnetization and confirms that it could be easily separated with an external magnet, and showed 85.3% of degradation efficiency even after 6 recycles which indicated its higher stability and recyclability. Thus, our study provides new insight into hydrogen generation and phenol degradation using AgVO₃ based recyclable composites.

Ni-Co bimetallic decorated dodecahedral ZIF as an efficient catalyst for photoelectrochemical degradation of sulfamethoxazole coupled with hydrogen production

In this work, a NiCo bimetallic ZIF (BMZIF) dodecahedron material has been synthesized by the precipitation approach and then used for simultaneously photoelectrocatalytic degradation of sulfamethoxazole (SMX) and hydrogen production. The combination of Ni/Co loading in ZIF structure increased the specific surface area 1484 (m² g^-1) and photocurrent density (0.4 mA cm^-2), which can facilitate the good charge transfer efficiency. In presence of peroxymonosulfate (PMS, 0.1 mM), the complete degradation of SMX (10 mg L^-1) was achieved at initial pH of 7 within 24 min, with the pseudo-first-order rate constants of 0.18 min^-1 and TOC removal efficiency of 85 %. Radical scavenger experiments affirm that ^•OH radicals were the primary oxygen reactive species to drive the SMX degradation. Along with SMX degradation at the anode, the H₂ production was observed at the cathode (140 μmol cm^-2 h^-1), which was 1.5 and 3 times higher than that of Co-ZIF and Ni-ZIF, respectively. The superior catalytic performance of BMZIF was assigned to the distinctive internal structure and synergistic effect between ZIF and Ni/Co bimetals, which improves light absorption and charge conduction efficiency. This study may provide insight into the new way to treat polluted water and simultaneously produce green energy using bimetallic ZIF in a PEC system.

A Z-scheme BiYO3/g-C3N4 heterojunction photocatalyst for the degradation of organic pollutants under visible light irradiation

Photocatalysis is one of the fascinating fields for the wastewater treatment. In this regard, the present study deals with an effective visible light active BiYO₃/g-C₃N₄ heterojunction nanocomposite photocatalyst with various ratios of BiYO₃ and g-C₃N₄ (1:3, 1:1 and 3:1), synthesised by a wet chemical approach. The as-synthesised nanocomposite photocatalysts were investigated via different physicochemical approaches like Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electrons microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical studies to characterise the crystal structure, morphology, optical absorption characteristics and photoelectrochemical properties. The photocatalytic degradation ability of the prepared photocatalytic samples was also analysed through the degradation of RhB in the presence of visible light irradiation. Of all the synthesised photocatalysts, the optimised CB-1 composite showed a significant photocatalytic efficiency (88.7%), with excellent stability and recyclability after three cycles. O₂^•- and ^•OH radicals were found to act a major role in the RhB degradation using optimised CB-1 composite, and it possessed ~ 1 times greater photocurrent intensity than the pristine g-C₃N₄ and BiYO₃. In the present work, a direct Z-scheme heterojunction BiYO₃/g-C₃N₄ with a considerably improved photocatalytic performance is reported.

A novel S-scheme Ws2/BiYWO6 electrostatic heterostructure for enhanced photocatalytic degradation performance towards the degradation of Rhodamine B

Constructing S-scheme heterojunction between two semiconductor materials is an effective route to increase the photocatalytic degradation efficiency. Here, a novel S-scheme WS₂/BiYWO₆ heterojunction photocatalyst was prepared by wet chemical route. At the same time, the photocatalytic degradation performance of the fabricated materials was analyzed by the degradation of Rhodamine B under visible light. Of all prepared WS₂/BiYWO₆ composites, the 20 wt.% WS₂ loaded WS₂/BiYWO₆ composite exhibited an enhanced photocatalytic degradation ability than other prepared photocatalysts. Here, O₂^·- and ^·OH radicals are performing a pivotal role in the Rhodamine B degradation and the optimized composite shows greater photocurrent intensity than pure BiYWO₆ and WS₂, respectively. Also, the synthesized photocatalyst maintains its stability with negligible changes even after three cycles. Thereby, the constructed S-scheme WS₂/BiYWO₆ heterojunction is a potential material for the wastewater remediation.

Construction of direct FeMoO4/g-C3N4-2D/2D Z-scheme heterojunction with enhanced photocatalytic treatment of textile wastewater to eliminate the toxic effect in marine environment

A novel FeMoO₄/g-C₃N₄-2D/2D Z-scheme heterojunction photocatalyst was prepared via wet chemical method. The observed structural morphology of FeMoO₄/g-C₃N₄ reveals the 2D-iron molybdate (FeMoO₄) nanoplates compiled with the 2D-graphitic carbon nitride (g-C₃N₄) nanosheets like structure. The photocatalytic activity of the g-C₃N₄, FeMoO₄, and FeMoO₄/g-C₃N₄ composites were studied via the degradation of Rhodamine B (RhB) as targeted textile dye under visible light irradiation (VLI). The optimal FeMoO₄/g-C₃N₄ (1:3 ratio of g-C₃N₄ and FeMoO₄) composite show an enhanced degradation performance with rate constant value of 0.02226 min^-1 and good stability even after three cycles. Thus, the h+ and O₂^•－are the key radicals in the degradation of RhB under VLI. It is proposed that the FeMoO₄/g-C₃N₄ Z-scheme heterojunction effectively enhances the transfer and separation ability of e^-/h⁺ pairs, by the way increasing the photocatalytic efficiency towards the RhB degradation. Thus, the newly constructed Z-scheme FeMoO₄/g-C₃N₄ heterojunction photocatalyst is a promising material for the remediation of wastewater relevant to elimination of toxic effect in marine environment.

Construction of direct Z-scheme g-C3N4/BiYWO6 heterojunction photocatalyst with enhanced visible light activity towards the degradation of methylene blue

Construction of the Z-scheme heterojunction photocatalyst achieved highly improved photocatalytic ability by its high redox ability of the photoinduced e^--h⁺ pairs. In the study, Z-scheme g-C₃N₄/BiYWO₆ heterojunction photocatalyst is prepared by the single-step hydrothermal method. Further, its photocatalytic ability was assessed by degrading methylene blue under visible light exposure. Particularly, the optimized 30 wt% of g-C₃N₄ in the g-C₃N₄/BiYWO₆ composite exposes almost complete degradation after 90 min, that is ~ 3.0 times greater than the bare BiYWO₆ and g-C₃N₄ with the rate constant value 0.032 min^-1. Experimentally, the radical trapping studies indicate O₂·^- and ·OH radicals are playing a vital role in the photocatalytic degradation process. Also, the Z-scheme g-C₃N₄/BiYWO₆ heterojunction photocatalyst exhibits excellent photoelectrochemical property and it is stable after 5 cycles, which indicates its good reusability nature. These enhancements are due to the newly formed heterostructure that facilitates the migration and separation efficiency of the photoproduced e^--h⁺ pairs. Hence, the synthesized Z-scheme g-C₃N₄/BiYWO₆ heterostructure could be an excellent material for wastewater remediation works.

A facile synthesis of visible light driven Ni3V2O8 nano-cube/BiVO4 nanorod composite photocatalyst with enhanced photocatalytic activity towards degradation of acid orange 7

Photocatalysis is one of the promising method to degrade harmful organic pollutants under visible light exposure. In this work, a novel Ni₃V₂O₈/BiVO₄ nanocomposite has been prepared by one-pot hydrothermal method, and investigated through X-ray diffraction, FT-IR, UV-visible diffuse reflectance spectroscopy, scanning and transmission electron microscopy and photoluminescence techniques. Subsequently, the photocatalytic performance of Ni₃V₂O₈/BiVO₄ nanocomposite has been examined by degrading AO7 under visible light illumination. The photocatalytic efficiency of the optimized 1:2 ratio of Ni₃V₂O₈/BiVO₄ nanocomposite photocatalyst is found to be 87% with a rate constant value of 0.03387 min^-1 which are higher than those of other prepared photocatalysts. This nanocomposite exhibits excellent stability even after 3 three cycles, and shows 1.135- and 1.17-times higher photocurrent intensity than pure BiVO₄ and Ni₃V₂O₈ respectively. The mechanism for the degradation of AO7 over Ni₃V₂O₈/BiVO₄ nanocomposite photocatalyst has been proposed.

A novel Fe/Mo co-catalyzed graphene-based nanocomposite to activate peroxymonosulfate for highly efficient degradation of organic pollutants

A novel 3D α-FeOOH@MoS₂/rGO nanocomposite was successfully fabricated by a simple in situ hydrothermal method. It is a highly efficient heterogeneous catalyst in activation of peroxymonosulfate (PMS) for rapid degradation of rhodamine B (RhB), with 99.9% of RhB removed within 20 min. The introduction of rGO contributes to uniform dispersion and sufficient contact of α-FeOOH and MoS₂ nanosheets. Highly active Mo(IV) enhances the reduction of Fe(III), improves Fe(III)/Fe(II) conversion and promotes the generation of O₂1, which ensures an improved catalytic activity. MoS₂/rGO hybrid can effectively solve the problem of material reunion and make α-FeOOH exhibit excellent catalytic performance. The α-FeOOH@MoS₂-rGO/PMS system is a co-catalytic system based on the active components of α-FeOOH and MoS₂. The main reactive oxygen species in the α-FeOOH@MoS₂-rGO/PMS system are O₂1, SO₄^.- and ⋅O₂^-, which contribute to a high reactivity over a wide range of pH (5-9). Besides, this system is highly resistant to anions (Cl^-, SO₄^2-) and natural organic matter (humic acid), and can be widely used for degradation of common organic pollutants. The α-FeOOH@MoS₂/rGO is a promising Fenton-like catalyst for refractory organic wastewater treatment.

Electrospun composite nanofibers as novel high-performance and visible-light photocatalysts for removal of environmental pollutants: A review

Environmental pollution caused by industries and human manipulations is coming a serious global challenge. On the other hand, the world is facing an energy crisis caused by population growth. Designing solar-driven photocatalysts which are inspired by the photosynthesis of plant leaves is a fantastic solution to use solar energy as green, available, and unlimited energy containing ∼50% visible light for the removal of environmental pollutants. The polymeric and non-polymeric-based electrospun composite nanofibers (NFs) are as innovative photocatalytic candidates which increase photocatalytic activity and transition from UV light to visible light and overcome the aggregation, photocorrosion, toxicity, and hard recycling and separation of the nanosized powder form of photocatalysts. The composite NFs are fabricated easily by either embedding the photocatalytic agents into the NFs during electrospinning or via their decorating on the surface of NFs post-electrospinning. Polyacrylonitrile-based, tungsten trioxide-based, zinc oxide-based, and titanium dioxide-based composite NFs were revealed as the most reported composite NFs. All the lately investigated electrospun composite NFs indicated long-term stability, high photocatalytic efficiency (∼> 80%) within a short time of light radiation (10-430 min), and high stability after several cycles of use. They were applied in various applications including degradation of dyes/antibiotics, water splitting, wastewater treatment, antibacterial usage, etc. The photogenerated species especially holes, O₂^∙-, and ^.OH were mostly responsible for the photocatalytic mechanism and pathway. The electrospun composite NFs have the potential to use in large-scale productions in condition that their thickness and recycling conditions are optimized, and their toxicity and detaching are resolved.

2D/1D BiOI/g-C3N4 nanotubes heterostructure for photoelectrochemical overall water splitting

To boost the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances, the BiOI/graphitic carbon nitride nanotubes (g-C₃N₄ nanotubes) heterojunction was synthesized herein through the hydrothermal method. BiOI in-situ grew on the surface of g-C₃N₄ nanotubes derived from melamine. The rapid recombination between photoexcited electrons and holes of pristine semiconductors was prevented via building the stable heterojunction. The SEM results indicated that the BiOI was wrapped around the surface of g-C₃N₄ nanotubes, resulting in an optimized electronic transmission pathway. Much lower charge transfer resistance at the p-n heterojunction was demonstrated compared with pristine BiOI according to the EIS results, thus leading to the faster surface reaction rates. Moreover, the composite exhibited both outstanding OER and HER activities under illuminated conditions. This study may shed light upon establishing a bifunctional photoelectrocatalysis for photoelectrochemical water splitting based on stable 2D metal and 1D metal-free nanocomposite.

Synthesis of novel graphene aerogel encapsulated bismuth oxyiodide composite towards effective removal of methyl orange azo-dye under visible light

Development of novel and eco-friendly composite photocatalysts for the efficient removal of contaminants from wastewater is the need of the hour. In this study, visible light responsive novel graphene aerogel/bismuth oxyiodide (GA/BiOI) composite was synthesized via low-temperature solvothermal method. The synthesized GA/BiOI composite was tested for methyl orange (MO) azo-dye degradation under visible light. The graphene aerogel nanosheets were wrapped onto the surface of the each individual BiOI microsphere, which encourages the interconnection charge transfer process. The light absorption properties of GA/BiOI composite were increased with the addition of graphene aerogel. The optimal 5%-GA/BiOI composite displayed higher MO removal efficiency, which is ∼2 fold more than the bare BiOI photocatalyst. This enhanced photocatalytic activity was on account of lower recombination rate of charge carriers, improved light absorption, and the high surface area. In addition, the 5%-GA/BiOI composite showed good stability until 3 cycles without deactivation. The plausible MO degradation mechanism was also proposed over GA/BiOI under visible light. This work provides a new perspective on the design and synthesis of graphene aerogel-based composite for environmental applications.

Efficient photocatalytic degradation of emerging ciprofloxacin under visible light irradiation using BiOBr/carbon quantum dot/saponite composite

The use of visible-driven photocatalysts has fascinated attention as a capable and sustainable approach for wastewater remediation. In this work, BiOBr/carbon quantum dot (CQDs)/saponite composites (CQDs/Clay@BiOBr) were fabricated via hydrothermally using two different CQDs/Clay precursors (in-situ synthesis (IS) and physical mixing (PM)). The obtained products were characterized, and the photocatalytic performances of the prepared samples were evaluated in the photocatalytic decomposition of emerging ciprofloxacin (CIP) pharmaceutical waste. The highest CIP mineralization performance was achieved when a combination of BiOBr and CQDs/Clay (IS) with the appropriate proportion because the strong adhesion between CQDs and clay generate a great heterojunction in the composite. The stronger interaction of CQDs and better distribution of CQDs on the surface of clay in the CQDs/Clay (IS) enhanced the interaction of BiOBr and CQDs, and avoided the re-agglomeration of excess of CQDs on surface of BiOBr which reduce the active surface to receive the light and react with CIP. The ultrafast degradation rate of the optimized CQDs/Clay@BiOBr composite was better compared to others. The significant improvement in the CIP degradation efficiency of the CQDs/Clay@BiOBr composite was attributed to the excellent separation and transportation of photogenerated electrons and holes, as confirmed by photoluminescence, photocurrent density, and electrochemical impedance spectroscopy results. Moreover, the photocatalytic degradation mechanism of CIP in the CQDs/Clay@BiOBr composite was proposed based on the electronic states of each material in the composite and on a scavenger test. Thus, the proposed CQDs/Clay@BiOBr composite can be employed as a potential visible-light-driven photocatalyst for the decomposition of organic contaminants in wastewater.

Morphology-engineered carbon quantum dots embedded on octahedral CdIn2S4 for enhanced photocatalytic activity towards pollutant degradation and hydrogen evolution

In recent years, carbon quantum dots (CQDs) and CdIn₂S₄ have considered as the representatives of the most potential photocatalysts applied in the field of photocatalysis for efficiently solving energy shortage and environmental pollution. In this work, a novel CQDs hybridized CdIn₂S₄ (CQDs/CIS) heterostructure with 2D nanosheet/3D nanooctahedra morphology was successfully fabricated by a simple in-situ solvothermal method. Most interestingly, the morphology of hybrid gradually evolved from 3D octahedron to 2D nanosheet with the increase of CQDs. This unique 2D/3D structure and synergistic effect between CQDs and CdIn₂S₄ increased the multi-dimensional active reaction sites and enhanced the quantum yield and the separation efficiency of photogenerated electron pairs. Therefore, CQDs/CIS hybrids showed excellent photocatalytic activities of H₂ generation, RhB and TCH degradation. Especially, CQDs/CIS-3 heterostructure presented the highest photocatalytic efficiency and its hydrogen generation activity (956.79 μmol g^-1 h^-1) was 7.57-fold improvement by contrast with pure CdIn₂S₄ (126.35 μmol g^-1 h^-1). Moreover, RhB and TCH degradation rate constants of CQDs/CIS-3 were about 8.14 and 2.32 times higher than those of CdIn₂S_4, respectively. Furthermore, the effect of CQDs on the evolution of heterostructure morphology and photocatalytic mechanism were also proposed. This research work would offer useful enlightenment for elucidating the affect of CQDs on the morphology evolution and construction of CQDs-based hybrid with excellent performances for H₂ production and pollutant removal.

One-pot synthesis of bismuth yttrium tungstate nanosheet decorated 3D-BiOBr nanoflower heterostructure with enhanced visible light photocatalytic activity

A visible light driven BiOBr/Bi_xY_1-xWO₆ nanocomposite photocatalyst of various compositions are prepared by the addition of different amounts of KBr (0.5, 1.0, 1.5, 2.0 mmol) in Bi_xY_1-xWO₆ by a one-pot hydrothermal method. Furthermore, the photocatalytic properties of the as-prepared materials are analyzed by the decomposition of methylene blue under visible light illumination. In particular, the BiOBr/Bi_xY_1-xWO₆ nanocomposite prepared by taking 1.5 mmol of KBr present a superior photocatalytic ability (78.3%) with the rate constant value 0.016 min^-1, a low bandgap (E_g = 2.51 eV) as well as photoluminescence emission intensity than other photocatalysts prepared in this study. The radical scavenging studies revealed that OH and h⁺ performed an imperative role in the decomposition of methylene blue. Furthermore, the optimized photocatalyst is stable even after four cycles, which exposes the excellent photostability and reusability properties of the photocatalyst. In addition, a plausible mechanism of decomposition of methylene blue under visible light irradiation is also proposed.

Solvothermal synthesis of 3D hierarchical Cu2FeSnS4 microspheres for photocatalytic degradation of organic pollutants

In this work, we prepared Cu₂FeSnS₄ (CFTS) microspheres via solvothermal method and studied their photocatalytic performance towards the degradation of organic pollutants. With increasing solvothermal temperature from 160 °C to 180 °C, the morphology of CFTS changes from irregular 2D to hierarchical 3D shapes. Hierarchical 3D CFTS microspheres packed with 2D nanosheets were successfully prepared at 180 °C. During the solvothermal process, octadecyl amine (ODA) acts as a capping agent to prevent the aggregation of particles, while L-cystine functions as an environmentally friendly sulfur source and complexing reagent. The large surface area and mesoporous structure of the as-prepared 3D hierarchical CFTS microspheres provide more active sites, enhance visible light absorption and promote charge separation and transfer, leading to the improved photodegradation performance for RhB and MB compared to the samples prepared at the temperature lower than 180 °C. This work provides a simple and low-cost method for the synthesis of 3D hierarchical CFTS towards photocatalytic applications.

Efficient Visible-Light-Responsive Ag3PO4/g-C3N4/Hydroxyapatite Photocatalyst (from Oyster Shells) for the Degradation of Methylene Blue: Preparation, Properties and Mechanism

A novel ternary Ag3PO4/g-C3N4/hydroxyapatite photocatalyst was prepared, and its morphology, composition and structure were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and electron spin resonance, etc. The results show that g-C3N4 is evenly dispersed in the interior of hydroxyapatite, forming a homogeneous composite, and significantly improves the band gap structure of the material as a whole. Ag3PO4/g-C3N4/hydroxyapatite has good electron transfer ability and an appropriate energy band structure, which shows that the material has a good degradation effect and stability. Finally, based on the characterization and experimental results, a possible Z-scheme mechanism was proposed, and the active species involved in the reaction are mainly O2− and h+.

Synthesis and characterization of Ag-AgVO3/Cu2O heterostructure with improved visible-light photocatalytic performance

Heterostructure Ag-AgVO3/Cu2O photocatalyst was prepared by the hydrothermal procedure. The prepared photocatalysts were characterized by different physico-chemical techniques. For Ag-AgVO3/Cu2O composites, AgVO3 shows the monoclinic phase whereas Ag and Cu2O show a cubic phase. SEM images of Ag-AgVO3/Cu2O composites illustrated that the surface of AgVO3 nanorods was covered by Ag and Cu2O nanoparticles. Ultra violet - visible diffuse reflectance spectra revealed that the calculated optical response of Ag-AgVO3/Cu2O composite was found to be 2.24 eV. Additionally, the composite catalyst demonstrated improved photo-efficiency for the decolorization of methylene blue dye compared to that of pristine AgVO3. The better performance of the composite sample can be ascribed to its high charge separation and inhibition in recombination of charges in Ag-AgVO3/Cu2O catalyst Finally, this heterostructure Ag-AgVO3/Cu2O catalyst demonstrated good stability which simply can be recycled a number of times with steadiness; thus, unwraps new possibilities for applications as innovative photocatalyst.