Visible Light Photocatalytic Activity Research Articles

Multifunctional visible light photocatalytic carbon dots synergize with reactive oxygen species for anti-quorum sensing and anti-bacteria for salmon preservation

Quorum sensing (QS)-induced spoilage causes approximately 15–20% of annual food wastage. However, traditional natural QS inhibitors exhibit poor water solubility and no catalytic activity. Therefore, this study aimed to synthesize novel anti-QS carbon dots (RR-CDs) with good water solubility, visible light photocatalytic activity, and high biocompatibility. The RR-CDs (<200 μg mL−1) exhibited considerable broad-spectrum antibacterial activity by generating reactive oxygen species (ROS) to disrupt the cell membrane wall structure. Owing to the appropriate bandgap of RR-CDs, a high ROS content, including ·O2−, 1O2, and ·OH, was generated via energy transfer under visible light irradiation. Furthermore, the combined effect of RR-CDs and ROS reduced the biofilm formation, swarming, swimming, and extracellular protease production of Pseudomonas fluorescens by 48.45%, 25.51%, 52.79%, and 38.67%, respectively, by inhibiting LuxI/R expression, which further decreased pgaC, tyrB, motB, and aprE expression by >50 %. Notably, RR-CDs exhibited no obvious cytotoxicity; furthermore, they could extend the shelf life of salmon by 3 d. Altogether, these results present and validate the strong ability of photocatalytic RR-CDs for QS inhibition and show their potential in aquatic product preservation.

Efficient simultaneous removal of phosphate and microcystin-LR in water using a novel g-C3N4/calcite composite under dark-visible light cycles

Harmful algal blooms (HABs) associated with the abundant presence of phosphorus and microcystin in natural waters have raised a growing global concern. In this study, an adsorption-photocatalysis strategy was developed using a novel g-C3N4/calcite composite for efficient simultaneous removal of phosphate and microcystin-LR in water under dark-visible light cycles for the first time. The appropriate introduction of calcite into g-C3N4 (i.e., g-C3N4/calcite-1) was efficient in both phosphate adsorption (>78.5 %) and microcystin-LR degradation (>84.3 %) under a dark-visible light cycle of 3:3h at an optimal dosage of 100 mg/L in waters (pH 5–9 and temperature 10–40 °C). The simultaneous removal mechanisms proposed that g-C3N4/calcite-1 adsorbed phosphate via adsorption and precipitation with surface Ca2+, and degraded microcystin-LR via oxidation by photogenerated reactive species (mainly h+ and •OH). The material characterizations and density functional theory (DFT) calculations revealed that the combination of g-C3N4 and calcite could not only change the electric field distributions of calcite and optimize the charge transfer during adsorption to improve its adsorption capacity towards phosphate, but also narrow the band gaps of g-C3N4, promote the electron-hole separation and lower the first-step reaction barrier in oxygen reduction pathway during photocatalysis to enhance its visible-light photocatalytic activity towards microcystin-LR. Collectively, these findings are believed to offer valuable insights on the green material design for water environmental remediation and the underlying mechanism elucidation for simultaneous removal of phosphorus and microcystin in water to achieve effective comprehensive management of HABs.

Enhancement of visible light adsorption and photocatalytic degradation activity of organic dye by coating semiconducting TiO2 shell on plasmonic Au particles

The plasmonic effect enhances light absorption in semiconductor photocatalysts, while the noble metal-semiconductor interface promotes charge carrier transfer and separation, boosting photocatalytic activity. However, current methods for synthesizing metal-core TiO2-shell nanoparticles face challenges, such as keeping stable and preventing aggregation. This study presents a simple and moderate synthesis method for Au@TiO2 core-shell nanoparticles, enabling precise control over the TiO2 shell thickness and stable photocatalytic performance. Various characterization techniques were employed to assess the optical and structural properties of the synthesized Au@TiO2 core-shell nanostructures. The results demonstrated that increasing the Au core concentration led to a gradual decrease in TiO2 shell thickness. The adsorption properties and photocatalytic degradation efficiency of the synthesized Au@TiO2 core-shell nanostructured catalysts were thoroughly examined, particularly focusing on their performance with methyl orange (MO) and methylene blue (MB). Au@TiO2 achieved excellent adsorption performance for MO, with a maximum capacity of 231±6 mg/g. Furthermore, Au@TiO2 exhibited higher photocatalytic degradation activity of both MO and MB than pure TiO2. The mechanism study indicated that it attributed to enhanced visible light absorption, reduced bandgap, and higher valence band energy. Additionally, the Au@TiO2 catalysts showed good cyclic stability, making them promising for future applications. This research offers insights into designing efficient photocatalysts, addressing existing synthesis challenges, and contributing valuable references for future advancements.

Preparation, characterization and emission of Na3-3xLnxFe2(PO4)3 (Ln = Eu, Tb; 0 ≤ x ≤ 0.1 mol %) and photocatalytic activity of Na3Fe2(PO4)3

Rare earth doped compositions Na3-3xLnxFe2(PO4)3 (x = 0, 0.025, 0.05, 0.075 and 0.1) were prepared by ion-exchange method using Na3Fe2(PO4)3 and LnCl3 (Ln = Eu and Tb). Pristine Na3Fe2(PO4)3 was obtained by ethylene glycol assisted gel burning procedure. The phase characterization was performed by powder X-ray diffraction (XRD). All the compositions were well crystalized in monoclinic lattice. The FE-SEM images and elemental mapping were obtained. The infrared and Raman profiles of all-compounds were dominated by the bands owing to the (PO4) units. Investigation on photoluminescence emission and excitation spectra of Ln3+ (Ln = Eu, Tb) were carried out. The excitation spectra of Na3-3xLnxFe2(PO4)3 (Ln = Eu and Tb) gave intensive band at 256 (370) nm for Eu (Tb) doped phosphors. The photoluminescence emission spectra of Ln3+ (Ln = Eu, Tb) were carried out. The emission spectra of these composition were characterized by f -f transitions corresponding to 613 (5D0→7F2) for Eu and 543 (5D4→7F5) for Tb doped compositions. The maximum emission intensity for Eu (Tb) doped phosphors was found at x = 0.075 (0.05). The analysis of CIE and CCT values of all prepared phosphors were also carried out. Decay curves were analyzed in detail. The visible-light photo-catalytic activity of parent Na3Fe2(PO4)3 was examined against decomposition of methylene blue and methyl orange dyes. Parent Na3Fe2(PO4)3 exhibits good efficiency against MB (≈94.5 %) and moderate efficiency against MO (≈64 %) in 180 min of visible light irradiation. Scavengers’ experiments were carried to identify the active species during photodegradation.

Oxygen-doped Porous Ultrathin Graphitic Carbon Nitride Nanosheets for Photocatalytic Hydrogen Evolution and Rhodamine B Degradation.

Graphite phase carbon nitride (g-C3N4) is a highly promising metal-free photocatalyst. However, its applicability is restricted by low activity, due to weak quantum efficiency and small specific surface area. Exfoliating bulk crystals into porous thin-layer nanosheets and introducing element doping have been shown to improve photocatalytic efficiency, but these methods are often complex, time-consuming, and costly processes. In this study, we successfully synthesized porous oxygen-doped g-C3N4 (OCN) nanosheets utilizing a straightforward method. Our findings show that OCN have much higher light absorption and visible-light photocatalytic activity than bulk g-C3N4 (BCN) and nonporous g-C3N4 (CN). The OCN photocatalyst has a remarkable hydrogen evolution reaction (HER) rate of 8.02 mmol·g-1 h-1, which is 8 times greater than BCN. Additionally, the OCN shows a high degradation rate of 97.3% for Rhodamine B (RhB). This enhanced photocatalytic activity is ascribed to the narrow band gap and superior electron transfer capacity. Our findings suggest a potential technique for generating efficient g-C3N4 photocatalysts.

Effective removal of organic compounds by g-C3N4-AQ/Fe(III) via photocatalytic oxidation and photochemical cycling of iron

Anthraquinone-anchored graphitic carbon nitride (denoted as g-C3N4-AQ), which has been reported in the photochemical production of H2O2, demonstrated significant visible light photocatalytic activity with Fe(III) for the degradation of organic compounds. The synthesized g-C3N4-AQ exhibited a light absorption spectrum and crystallinity comparable to that of pristine g-C3N4. FT-IR and XPS analyses confirmed the covalent bonding between AQ and g-C3N4. The synthesized g-C3N4-AQ generated 12 μM of H2O2 within 2 h under visible light illumination, a quantity negligible for the degradation of organic compounds. However, in the combination with Fe(III), the system successfully degraded organic compounds, achieving degradation of 88 – 99 % in the presence of dissolved oxygen. It was also observed that the photochemical activity of g-C3N4-AQ/Fe(III) was non-selective towards the target organic compounds. Intriguingly, the visible light-illuminated g-C3N4-AQ/Fe(III) selectively degraded target organic compounds in the absence of dissolved oxygen. Experimental work employing reactive oxidant scavengers and oxidant probes revealed that •OH is the main reactive species responsible for the degradation of organic compounds in the presence of dissolved oxygen, whereas in its absence, the hole acts as the primary oxidant in the selective degradation of organic compounds. This finding provides important insights into the application of the g-C3N4-AQ/Fe(III) system for effective micropollutant removal.

Construction of Magnetically Retrievable g-C3N4/CeO2-Fe3O4-Reduced Graphene Oxide Composites With Enhanced Visible-Light Photocatalytic Activity And Antibacterial Properties

Construction of Magnetically Retrievable g-C3N4/CeO2-Fe3O4-Reduced Graphene Oxide Composites With Enhanced Visible-Light Photocatalytic Activity And Antibacterial Properties

Adsorption Performance and Photocatalytic Activity of La-TiO2@kaolin Composites

Abstract La-TiO2@kaolin(LTK) composites were prepared via sol-gel method with kaolin, lanthanum nitrate and tetrabutyl titanate as raw materials. The samples were characterized by XRD, SEM/EDS, and UV-Vis. The visible light photocatalytic reduction activity and adsorption performance of samples for Cr(VI) were studied. The results showed that La doping can refine TiO2 grains, stabilize phase structure of anatase TiO2, and expand its absorption spectrum, thereby enhancing its photocatalytic reduction activity. Due to the composite of kaolin, the dispersion of TiO2 is improves and it is endowed with a large specific surface area lead to enhance its adsorption ability for Cr(VI). The adsorption equilibrium process of LTK for Cr(VI) conforms to the Langmuir equation model. The coupling effect of doping and composite modification improves the adsorption and visible light catalytic reduction activity of Cr(VI) over composite material samples. The adsorption-photocatalytic removal rate of LTK for Cr(VI) under visible light irradiation for 6 hours reached the highest of 96.5%. The apparent first-order kinetic constant of its photocatalytic reduction reaction was 2.6 times that of pure TiO2.

Photocatalytic degradation of phenol and polycyclic aromatic hydrocarbons in water by novel acid soluble collagen-polyvinylpyrrolidone polymer embedded in Nitrogen-TiO2

Herein, we have synthesized acid-soluble collagen (ASC), polyvinylpyrrolidone (PVP), and nitrogen-doped titanium dioxide to form a novel hybrid photocatalyst nanocomposite (N-TiO2/ASC-PVP). The results of XRD, SEM and TEM revealed that the as-synthesized photocatalyst was composed of spheroidal particles, which were smaller than undoped TiO2.XPS analysis revealed that N was effectively incorporated into the lattice of TiO2 through substituting oxygen atoms, and N might coexist in the form of substitutional N (O–Ti–N) and interstitial N (TiON). The N-TiO2/ASC-PVP composite calcined at 200 and 400 °C exhibited high photocatalytic degradation rates for phenol, naphthalene (Nap), fluoranthene (Flu), phenanthrene (Phe), pyrene (Pyr), benz[a]anthracene (BaA), and anthracene (Ana), achieving a 98.6 % removal rate within 120 min at a dosage of 10 mg/L. The enhanced visible light photocatalytic activity was mainly attributed to the smaller crystal size, more surface hydroxyl groups, stronger light absorption in visible region and narrower band gap energy. This innovative hybrid photocatalyst holds immense potential for applications in materials science and nanotechnology, promising to revolutionize various industries.

Bismuth-based nanocomposites as potential materials for indoor air treatment

Air pollution is a worldwide health hazard; thus, improving air quality is a demanding need. Photocatalysis is a robust strategy for air treatment. The boosted activity of the photocatalytic system depends on tuning their properties for the particular application. BiOX (X: Cl, I) compounds are emergent photocatalytic systems with numerous advantages for air treatment. However, their optical properties (Eg) and fast recombination of active species (e−/h+) limit their practical applications. In this study, we remark on the properties of BiOX-GO systems for indoor air purification. We use a microwave-activated solvothermal technique to synthesize the nanomaterials (NMs). BiOX NMs exhibit hierarchical 3D structures, crystallinity, and tunable optical absorption properties. BiOX-GO composites present an enhanced visible-light photocatalytic activity due to the electron acceptor capacity of GO and modification of Eg. The indoor air disinfection capacity of the NMs ranked as follows: BiOCl-GO (96.7%) > BiOI-GO (96.2%) > BiOI (89.2%) > BiOCl (79%). The higher efficiency under visible light of BiOCl-GO can be related to the presence of oxygen vacancies, strong oxidation potential, and single crystalline phase of the materials. Due to the abundance and biocompatibility of bismuth-containing compounds, together with their enhanced visible light activity, BiOX become potent candidates for environmentally sustainable remediation technologies.

Enhanced visible light photocatalytic activity of Pt cluster modified carbon nitrides for U(VI) removal

Photocatalysis has been regarded as one of the effective methods of removing U(VI) from radioactive wastewater in recent years, due to the benefits of being environmentally friendly and efficient. In this work, a Pt cluster modified carbon nitride photocatalyst (Pt-CN) was synthesized in zinc chloride molten salt. The photocatalysts were characterized by XRD, IR, XPS, UV–vis, PL and EIS. The result demonstrated that the doping of Pt makes Pt-CN show higher electronic conductivity and better charge separation and migration, leading to an enhanced photocatalytic activity and faster kinetics compared with bulk graphitic carbon nitride (g-C3N4). Moreover, for uranium contained solution photocatalytic treatment, Pt-CN reached 94.6 % removal efficiency after 300 min of illumination with Xe light, and the kinetics improved by a factor of three compared to that of g-C3N4. Furthermore, the good reusability and photostability of the Pt-CN was confirmed as the removal efficiency remained at 83.7 % even after being recycled and reused five times. The photocatalytic reaction product was characterized as (UO2)O2·2 H2O, and the mechanism was deduced as uranium species reacting with H2O2 generated by light illumination in an open system. This molten salt one-step synthesis and Pt doping method and the performance of U(VI) extraction in air showed a promising potential for the application of Pt-CN for U(VI) extraction and removal from water.

In-situ constructing oxygen-enriched vacancies BiOCl with 3D flower-structure for exceptional visible-light-driven photocatalytic properties

Bismuth oxychloride (BiOCl), emerging as a novel environmentally friendly nanomaterial, possesses considerable potential for photocatalytic degradation of organic wastewater. However, inadequate active sites and inhibited electron separation efficiency severely hinder its visible-light photocatalytic activity. To address this issue, herein we present a facile approach to in-situ construct BiOCl three-dimensional (3D) flower-structure (BOC-F) with oxygen-enriched vacancies for abundant active sites and effective electron separation efficiency through morphology control and vacancy engineering. The visible photocatalytic activity of BOC-F and BiOCl with 2D flaky-structure (BOC-S) was assessed through a systematic examination of the degradation efficiencies of tetracycline hydrochloride (TC-HCl) and rhodamine B (RhB). Under visible light irradiation, BOC-F exhibited superior visible photocatalytic activity, effectively degrading tetracycline hydrochloride (TC-HCl) (20 mg/L) and rhodamine B (RhB) (200 mg/L) within 90 min and 20 min of light exposure, respectively. The findings elucidate that BOC-F, possessing a 3D flower structure, manifests a heightened concentration of oxygen vacancies in contrast to BOC-S, consequently yielding excellent performance. Moreover, The ESR test showed that singlet oxygen (1O2) and hole (h+) were two main active species in the photocatalytic degradation of BOC-F. This work not only furnishes a facile method for constructing oxygen-rich vacancies in BiOCl but also provides fresh insights into the potential for enhancing the visible photocatalytic properties of Bi-based materials through vacancy engineering.

Plasmonic Au-MoS2 Nanohybrids Using Pulsed Laser-Induced Photolysis Synthesis for Enhanced Visible-Light Photocatalytic Dye Degradation.

The Au-MoS2 nanocomposites (NCPs) exhibit excellent visible-light photocatalytic activity and potential applications in the photocatalytic degradation of organic dyes. In this study, an Au-MoS2 heterojunction structure with Au nanoparticles (NPs) deposited on MoS2 nanosheets was synthesized via the pulsed laser-induced photolysis method. The influence of Au content on the photocatalytic performance was systematically investigated, and the working mechanism under visible light excitation was elucidated. The optimal Au-MoS2 NCPs exhibited efficient degradation of methylene blue (MB) dye, mainly attributed to the plasmon resonance effect of Au NPs which facilitated the visible light harvesting and hot electron injection. The Au/MoS2 interface promoted the separation and transfer of photogenerated charge carriers. The electrostatic adsorption between positively charged MB molecules and the negatively charged MoS2 surface favored the affinity toward active sites. Furthermore, the photogenerated electrons and holes participated in generating reactive oxygen species such as superoxide and hydroxyl radicals, which initiated the oxidative degradation of MB. The PLIP-introduced Au NPs not only endowed the material with excellent visible light responsivity but also possibly modulated the electronic structure and photocatalytic active sites of MoS2 through an intrinsic effect, providing new insights for further enhancing the photocatalytic performance of Au-MoS2 NCPs.

Energy-saving synthesis of wurtzite ZnS nanoparticles using Yttrium as a defect regulator by hydrothermal method

In this work, Y-doped ZnS nanoparticles were synthesised using the hydrothermal method with doping percentages of 0.5%, 1%, 2.5%, and 5%. XRD study revealed that doping caused a phase transition from cubic to hexagonal, further confirmed by Raman analysis and TEM images. Morphological studies conducted by SEM and TEM provided insights into the structural changes. Diffused reflectance studies were used to evaluate the band gap, with values obtained as 3.33eV, 3.45 eV, 3.45 eV, 3.44 eV, and 3.37 eV for pure, 0.5%, 1%, 2.5%, and 5% Y-doped ZnS, respectively. Photoluminescence analysis revealed the presence of defect states in ZnS nanoparticles, indicated by peaks at 362 nm, 383 nm, and 390 nm in both pure and doped samples. The intensity of these peaks increased with Y doping, attaining its highest at 1% Y doping, while concentration quenching was observed at higher doping percentages. The EDAX analysis confirmed the successful integration of Y as a dopant in the ZnS lattice. These findings highlight the importance of optimizing the doping concentration to achieve the desired luminous features and provide valuable insights into the doping-dependent luminescence behaviour of Y-doped ZnS nanoparticles. The visible light photocatalytic activity of the nanoparticles was investigated, and it was revealed that the photocatalytic efficiency increased initially and then declined with the doping concentration increased. It was found that the ideal doping concentration for 93% degradation efficiency was 1%. The novelty of this work lies in developing a simple and energy-saving method for synthesizing hexagonal ZnS at low temperatures, which avoids the need for high temperatures and advanced anti-oxidation apparatus.

Construction of cobalt-decorated Ag2WO4/g-C3N4 recombination-delayed nano-heterojunction for enhanced visible light photocatalytic activity

The strong photo-induced charge separation /transfer plays an essential function in improving the photocatalysis efficiency of Ag2WO4 nanoparticles (AWO NPs). Herein, the novel Ag2WO4/Co/g-C3N4 (ACG) nanocomposite (NCs) was fabricated via the ultrasonic and facile co-precipitation approach for the assessment of photocatalytic activity. Physiological and photoelectrochemical techniques investigated the optical characteristics, phase structures, morphology, and charge separation of pristine and ACG NCs. The crystalline nature of the fabricated nanomaterials was verified by XRD and a selected area electron diffraction (SAED) pattern. According to the optical properties of ACG NCs, the particle has a band gap energy of 2.7 eV, which allows it to break down brilliant cresyl blue (BCB) in the existence of visible light (VL). The findings show that the photocatalytic degradation performance of ACG NCs for BCB (97.46%) was greater than that of individual g-C3N4 nanosheets (GCN NSs) (40.4%) and AWOs (58.78%). The produced photocatalyst exhibited an outstanding performance for the BCB dye degradation and the reaction mechanism obeyed the pseudo-first-order kinetics of the Langmuir-Hinshelwood model. Through a radical trapping experiment, it was determined that the •OH and •O2 radicals were primarily accountable for the catalytic activity involved in the degradation of BCB. Six rounds of testing were used to examine the reusability of ACG NCs, and the reusable efficiency was 93.04%. The hazardous organic contaminants found in the environmental water bodies may be rapidly eliminated with the use of the produced NCs.

Novel visible-light activated photocatalytic ultrafiltration membrane for simultaneous separation and degradation of emerging contaminants

Emerging contaminants (ECs) in secondary effluent of wastewater treatment plants (WWTPs) have received increasing attention due to their adverse effects on aquatic ecosystems and human health. Herein, visible-light responsive photocatalyst TM (TiO2 @NH2-MIL-101(Fe)) and resultant photocatalytic ultrafiltration (PUF, PVDF/TM) membrane were prepared to remove 32 typical compounds of antibiotics, 296 compounds of antibiotic resistance genes (ARGs), and their corresponding bacterial hosts. The construction of heterojunction photocatalyst promoted the electron transfer from NH2-MIL-101(Fe) to TiO2 and the formation of N-TiO2, enhancing visible-light (λ ≥ 420 nm) photocatalytic activity. With highly-hydrophilic surface and delicately-regulated pore structure, the initial water permeance of optimal PUF membrane significantly increased to 3912.2 L/m2/h at 1.0 bar. Meanwhile, membrane retention (via adsorption, electrostatic interaction, and steric hindrance) was improved due to the narrowed pore size, highly-negative surface charge and abundant functional groups. Additionally, hydroxyl radical (•OH) was the dominant active reactive oxygen species (ROS) for ECs degradation, and the narrowed pore structure could serve as microreactors to increase ROS concentration and reduce migration distance. Consequently, the removal efficiencies of antibiotics, bacteria and ARGs were 86.5 %, 91.4 % and 91.8 %, respectively. Overall, this novel visible-light-activated PUF membrane expands membrane application, and has great potential in ECs treatment.

Mixed Redox-Couple-Involved Bornite Phase Cu5FeS4 as Efficient and Robust Cocatalysts for Greatly Enhanced Visible-Light Photocatalytic Activities

Mixed Redox-Couple-Involved Bornite Phase Cu₅FeS₄ as Efficient and Robust Cocatalysts for Greatly Enhanced Visible-Light Photocatalytic Activities

Preparation of core-shell like Bi2WO6/BiOCl heterojunction with excellent visible light photocatalytic activity

Constructing a ‘Z-scheme’ heterojunction is an effective method for improving photocatalyst activity. Core-shell like Z-scheme Bi2WO6/BiOCl heterojunction was synthesized through a two-step method. The arbutus-like BiOCl microsphere core was first gained by a solvothermal method. Then the Bi2WO6 nanosheet shell was in situ on the surface of the BiOCl microsphere through another solvothermal process. The Bi2WO6/BiOCl heterojunction had a much better photocatalytic performance than that of the single Bi2WO6, which was owing to the enlarged BET surface area, enhanced light absorption, and photocarriers migration. The photocatalytic mechanism of the Bi2WO6/BiOCl heterojunction was also proposed.

Rational regulation of post-electrodialysis electrochromic anion exchange membranes via TiO2@Ag synergistically strengthens visible-light photocatalytic anti-contamination activity

Membrane-contamination during electrodialysis (ED) process is still a non-negligible challenge, while irreversible consumption and unsustainability have become the main bottlenecks limiting the improvement of anion exchange membranes (AEMs) anti-contamination activity. Here, we introduce a novel approach to design AEMs by chemically assembling 4-pyndinepropanol with bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) in an electrochromic-inspired process. Subsequently, the co-mingled TiO2@Ag nanosheet with the casting-solution were sprayed onto the surface of the substrate membrane to create a micrometer-thick interfacial layer. The addition of Ag nanoparticles (NPs) enhances the active sites of TiO2, resulting in stronger local surface plasmon resonance (LSPR) effects and reducing its energy band gap limitation (From 3.11 to 2.63 eV). Post-electrodialysis electrochromic AEMs incorporating TiO2@Ag exhibit synergistic enhancement of sunlight absorption, effectively suppressing photogenerated carrier binding and promoting migration. These resultant-membranes demonstrate significantly improved bacterial inhibition properties (42.0-fold increase for E. coli) and degradation activity (7.59-fold increase for rhodamine B) compared to pure TiO2 membranes. Importantly, they maintain photocatalytic activity without compromising salt-separation performance or stability, as the spraying process utilizes the same substrate materials. This approach to rational design and regulation of anti-contamination AEMs offers new insights into the collaborative synergy of color-changing and photocatalytic materials.

Fabrication of a reusable carbon quantum dots (CQDs) modified nanocomposite with enhanced visible light photocatalytic activity

In awareness of industrial dye wastewater, carbon quantum dots (CQDs) and cobalt zinc ferrite (CZF) nanocomposites were synthesised for the making of carbon quantum dots coated cobalt zinc ferrite (CZF@CQDs) nanophotocatalyst using oxidative polymerization reaction. The results of TEM, zeta potential value, and FTIR confirm highly dispersed 1–4 nm particles with the − 45.7 mV carboxylic functionalized surface of CQDs. The results of the synthesised CZF@CQDs photocatalyst showed an average particle size of ~ 15 nm according to TEM, SEM, and XRD. The photocatalyst showed a 1.20 eV band gap, which followed the perfect visible light irradiation. TGA and DTA revealed the good thermal stability of the nanophotocatalyst. VSM was carried out, and the saturation magnetisations for CZF and CZF@CQDs were 42.44 and 36.14 emu/g, respectively. A multipoint study determined the BET-specific surface area of the CZF@CQDs photocatalyst to be 149.87 m2/g. Under visible light irradiation, the final CZF@CQDs nanophotocatalyst demonstrated remarkable efficiency (~ 95% within 25 min) in the photocatalytic destruction of Reactive Blue 222 (RB 222) and Reactive Yellow 145 (RY 145) dyes, as well as mechanical stability and recyclability. Even after the recycling of the degradation study, the nanophotocatalyst efficiency (~ 82%, 7th cycles) was predominantly maintained. The effects of several parameters were also investigated, including initial dye concentration, nanophotocatalyst concentration, CQD content, initial pH of the dye solution, and reaction kinetics. Degradation study data follow the first-order reaction rate (R2 > 0.93). Finally, a simple and low-cost synthesis approach, rapid degradation, and outstanding stability of the CQD-coated CZF nanophotocatalyst should make it a potential photocatalyst for dye wastewater treatment.