Search Results (65)

CO₂ laser processing has emerged as an efficient dry-finishing technique capable of inducing controlled chemical and morphological transformations in cotton and denim textiles. The strong mid-infrared absorption of cellulose enables localised photothermal heating, leading to selective dye decomposition, surface oxidation, and micro-scale ablation while largely preserving the bulk fabric structure. These laser-driven mechanisms modify colour, surface chemistry, and topography in a predictable, parameter-dependent manner. Low-fluence conditions predominantly produce uniform fading through fragmentation and oxidation of indigo dye; in comparison, moderate thermal loads promote the formation of carbonyl and carboxyl groups that increase surface energy and enhance wettability. Higher fluence regimes generate micro-textured regions with increased roughness and anchoring capacity, enabling improved adhesion of dyes, coatings, and nanoparticles. Compared with conventional wet processes, CO₂ laser treatment eliminates chemical effluents, strongly reduces water consumption and supports digitally controlled, Industry 4.0-compatible manufacturing workflows. Despite its advantages, challenges remain in standardising processing parameters, quantifying oxidation depth, modelling thermal behaviour, and assessing the long-term stability of functionalised surfaces under real usage conditions. In this review, we consolidate current knowledge on the mechanistic pathways, processing windows, and functional potential of CO₂ laser-modified cotton substrates. By integrating findings from recent studies and identifying critical research gaps, the review supports the development of predictable, scalable, and sustainable laser-based cotton textile processing technologies. Full article

Passive and active targets, both implanted with gold nanoprisms, were designed to achieve enhanced, uniform power absorption during two-sided illumination with short laser pulses. The capabilities of uniform, single-peaked Gaussian and adjusted nanoresonator number density distributions were compared. The average local E-field inside the gain medium and at the nanoprism surface was mapped as a function of the pump E-field strength and dye concentration, and the optimal parameters were selected based on the achievable local E-field. A comparative study was performed on passive and active targets to determine the most favorable distribution type and to consider the advantages of dye doping. The adjusted distribution is proposed for both passive and active targets. Dye doping is advantageous in all distributions as it results in decreasing the minimal standard deviation of the near-field enhancement (NFE), the delay of the minimal standard deviation in the power loss and deposited energy, and the standard deviation of the NFE, while increasing the FOM of the NFE in the uniform and adjusted distributions. Dye doping allows for decreasing the delay of the minimal standard deviation in the NFE, increasing the mean NFE, and decreasing the standard deviation of the power loss and deposited energy in the uniform, Gaussian, and adjusted distribution, respectively. Full article

CuWO₄ films were prepared on FTO glass substrates by the hydrothermal method. To improve their photocatalytic activity, the CuWO₄ films were further modified with BiOI using the successive ionic layer adsorption and reaction (SILAR) method. Characterization results indicate that BiOI and CuWO₄ achieved nanoscale mixing and formed a Type II p-n heterojunction. The heterojunction formation not only extends the light absorption threshold of CuWO₄ from 530 nm to 660 nm but also enhances the light absorption capacity across the entire solar spectrum. More importantly, the heterojunction formation facilitates the separation and transfer of photogenerated carriers and inhibits the recombination of photogenerated electrons and holes, which is evidenced by the results of PL spectra, photocurrent density, and EIS spectra. Compared with individual CuWO₄ films, the photocatalytic activity of BiOI/CuWO₄ heterojunction films in degrading the organic dye MB is increased by up to 1.17 times. Additionally, BiOI/CuWO₄ heterojunction films exhibit certain activity in the photocatalytic degradation of polystyrene (PS) nanoplastics and are capable of reducing the average particle size of nanoplastics from 425 nm to 325 nm within 80 h. Full article

The present study investigates dye-sensitized solar cells (DSSCs) incorporating natural extracts from the microalgae Spirulina and Chlorella as photosensitizers. TiO₂-based electrodes were prepared and immersed in methanolic algae extracts for 24 and 48 h. UV–Vis spectroscopy revealed absorption peaks near 400 nm and 650 nm, characteristic of chlorophyll. Electrochemical analyses, including photochronoamperometry and open-circuit potential, confirmed the photosensitivity and charge transfer capabilities of all systems. The cell sensitized with Chlorella after 48 h of immersion exhibited the highest energy conversion efficiency (0.0184% ± 0.0015), while Spirulina achieved 0.0105% ± 0.0349 after 24 h. Chlorella’s superior performance is attributed to its higher chlorophyll content and enhanced light absorption, facilitating more efficient electron injection and interaction with the TiO₂ surface. Although the efficiency remains lower than that of conventional silicon-based solar cells, the results highlight the potential of natural colorants as sustainable and low-cost alternatives for photovoltaic applications. Nonetheless, further, improvements are required, particularly in dye stability and anchorage, to improve device performance. This research reinforces the viability of natural photosensitizers in DSSC technology and supports continued efforts to optimize their application. Full article

Efficient photocatalysts based on composite materials are essential for addressing environmental pollution and enhancing water purification. This study presents a novel BiOI/V₂O₅ nanocomposite (BVNC) with a flower-like layered structure, synthesized via a low-temperature solvothermal process followed by high-pressure annealing for visible light (VL)-driven dye degradation and antibacterial activities. Compared to individual BiOI nanoparticles (BOINP) and V₂O₅ nanoparticles (VONP), under VL, the BVNC demonstrated significantly enhanced photocatalytic and antibacterial activity. The best-performing BVNC achieved a remarkable methylene blue degradation efficiency of 95.7% within 140 min, with a rate constant value 439% and 430% of those of BOINP and VONP, respectively. Additionally, BVNC exhibited high photocatalytic efficiencies for rhodamine 6G (94.0%), methyl orange (90.4%), and bisphenol A (69.5%) over 160 min, highlighting the superior performance of the composite materials for cationic and anionic dyes. Furthermore, BVNC established outstanding antibacterial capability against Staphylococcus aureus and Escherichia coli, demonstrating zones of inhibition of 12.24 and 11.62 mm, respectively. The improved catalytic and antibacterial capability is ascribed to the presence of a robust p-n heterojunction between BOINP and VONP, which broadens the photo-absorption range, reduces bandgap energy, and facilitates the significant separation of excitons and faster release of reactive oxygen species. Full article

β-galactosidase (β-Gal) has emerged as a pivotal biomarker for the comprehensive investigation of diseases associated with cellular senescence. The development of a fluorescent sensor is of considerable importance for precisely detecting the activity and spatial distribution of β-Gal. In this study, we developed two excited-state-altering responsive fluorescent sensors (TF1 and TF2) for ratiometric detection of β-Gal. Two TCF dyes, composed of tricyanofuran (TCF) and naphthol units, feature electron “pull–push” systems and are quenched fluorescence by β-Gal. Upon β-Gal hydrolysis, a significant ratiometric shift in absorption from ca. 475 nm to 630 nm is observed, accompanied by the emergence of a fluorescence signal at ca. 660 nm. The enzyme-responsive optical red-shifts are attributed to the excited-state transition from intramolecular charge transfer (ICT) state to local excited (LE) state, which was confirmed by density functional theory (DFT) calculations. Both fluorescent sensors display exceptional sensitivity and selectivity for the response of β-Gal in PBS solution and are capable of tracking β-Gal within senescent A549 cells. This study introduces a framework for developing multimodal optical probes by systematically modulating excited-state properties, demonstrating their utility in senescence studies, diagnostic assay design, and therapeutic assessment. Full article

This study explores the enhancement of photocatalytic activity in Zeolitic Imidazolate Framework-67 (ZIF-67), integrated with plasma electrolytic oxidation (PEO) coatings on an AZ31 magnesium alloy through post-treatment with potassium permanganate (KMnO₄). The KMnO₄ treatment induces the partial amorphization of ZIF-67, resulting in improved light absorption and the increased availability of catalytic sites. Structural and compositional analyses confirmed the formation of MnO_x species and amorphous domains that synergistically contribute to enhanced photocatalytic performance. Under visible light, the treated coatings demonstrated remarkable efficiency, degrading 99.43% of rhodamine B (RhB) dye within just 50 min, an improvement attributed to superior light absorption, enhanced charge separation, and the introduction of additional active sites. These findings establish KMnO₄ post-treatment as a transformative approach for optimizing MOF-based coatings, offering a pathway to develop advanced functional coatings with exceptional dye degradation capabilities. Full article

Microwave-assisted catalytic oxidation (MACO) is a novel wastewater treatment technology for the efficient treatment degradation of organic wastewater. However, a single carbon material or SiC has limited absorption of electromagnetic waves, and the efficiency of using it as a microwave-assisted organic catalyst is not satisfactory. To improve the absorption and microwave-assisted degradation performance of carbon matrix composites, a new carbon magnetic composite Ni@SiC/CNT/CNF microwave catalyst is constructed. By controlling the introduction of nickel, different numbers of carbon nanotubes are grown on the surface of carbon nanofibers, and C and SiC double-shell structures were formed on the top of the carbon nanotubes, which catalyzed the generation of active groups by the thermal effect generated by the plasma discharge under the action of microwave field, thus realizing the highly efficient catalytic degradation of wastewater dyes. The results show that the Ni@SiC/CNT/CNF with the lowest reflection loss of RL_min = −9.26 dB exhibit excellent degradation capabilities with a degradation efficiency of 99.9% for methylene blue within 90 s under 450 W microwave irradiation. Full article

Bentonite-supported TiO₂ (Montmorillonite (MMT)-TiO₂) and Cu₃TiO₅ oxides (MMT-Cu₃TiO₅) nanomaterials were synthesized via a facile and sustainable sol–gel synthesis approach. The XRD results indicate the presence of mixed phases, namely, TiO₂ anatase and a new semiconductor, Cu₃TiO₅, in the material. The specific surface area (S_BET) exhibits a notable increase with the incorporation of TiO₂ and Cu₃TiO₅, rising from 85 m²/g for pure montmorillonite to 245 m²/g for MMT-TiO₂ and 279 m²/g for MMT-Cu₃TiO₅. The lower gap energy of MMT-Cu₃TiO₅ (2.15 eV) in comparison to MMT-TiO₂ (2.7 eV) indicates that MMT-Cu₃TiO₅ is capable of more efficient absorption of visible light with longer wavelengths. The immobilization of TiO₂ and Cu₃TiO₅ on bentonite not only enhances the textural properties of the samples but also augments their visible light absorption capabilities, rendering them potentially more efficacious for adsorption and photocatalytic applications. The photocatalytic efficacy of both MMT-TiO₂ and MMT-Cu₃TiO₅ was evaluated through the monitoring of the degradation of Orange G, an anionic azo dye. The MMT-Cu₃TiO₅ photocatalyst was observed to induce complete degradation (100%) of the Orange G dye in 120 min when tested in an optimized reaction medium with a pH of 3 and a catalyst concentration of 2 g/L. MMT-Cu₃TiO₅ was demonstrated to be an exceptionally effective catalyst for the degradation of Orange G. Following the synthesis of the catalyst, it can be simply washed with the same recovered solution and reused multiple times for the photocatalytic process without the need for any chemical additives. Full article

Photoactive artificial nanocatalysts that mimic natural photoenergy systems can yield clean and renewable energy. However, their poor photoabsorption capability and disfavored photogenic electron–hole recombination hinder their production. Herein, we designed two nanocatalysts with various microstructures by combining the tailored self-assembly of the meso-tetra(p-hydroxyphenyl) porphine photosensitizer with the growth of titanium dioxide (TiO₂). The porphyrin photoabsorption antenna efficiently extended the absorption range of TiO₂ in the visible region, while anatase TiO₂ promoted the efficient electron–hole separation of porphyrin. The photo-induced electrons were transferred to the surface of the Pt co-catalyst for the generation of hydrogen via water splitting, and the hole was utilized for the decomposition of methyl orange dye. The hybrid structure showed greatly increased photocatalytic performance compared to the core@shell structure due to massive active sites and increased photo-generated electron output. This controlled assembly regulation provides a new approach for the fabrication of advanced, structure-dependent photocatalysts. Full article

Carbon nanomaterials are promising microwave catalytic materials due to their abundant inhomogeneous interfaces capable of producing ideal interfacial polarization and multiple relaxation, which are favorable for microwave attenuation and dissipation. However, the microwave absorption performance of carbon materials is not ideal in practical applications due to poor impedance matching and single dielectric loss. To solve this problem, a ternary system of “carbon-magnetic” Ni@SiC/CNFs (C/Ni, C/SiC) composites was synthesized by electrostatic spinning, and they efficiently degraded methylene blue under microwave radiation. The results imply that the catalyst Ni@SiC/CNFs with a double-shell structure gave a 99.99% removal rate in 90 s for the degradation of methylene blue under microwave irradiation, outperforming the C/Ni and C/SiC and most other reported catalysts in similar studies. On the one hand, the possible mechanism of the methylene blue degradation should be ascribed to the fact that the double-shell structure increases the polarization source of the material, resulting in excellent microwave absorption properties; and on the other, the in situ generation of ·OH and O₂⁻ active species under microwave radiation and the synergistic coupling effect of metal plasma greatly improved the degradation efficiency of methylene blue. The findings of this study could provide a valuable reference for the green degradation of industrial dye wastewater and its sustainable development process. Full article

Metal–organic frameworks (MOFs) have recently gained attention as a highly promising category of photocatalytic materials, showing great potential in the degradation of organic dyes such as Rhodamine B (RhB). Nonetheless, the mono-metal MOF materials in this application are often constrained by their limited light absorption capabilities and their propensity for recombination with carriers. The combination of different metal-based MOFs to form heterogeneous reactors could present a promising approach for the removal of dyes from water. In this work, a new CAU-17/MIL-100(Fe) Z-scheme heterojunction photocatalyst composed of two MOFs with the same ligands is reported to realize the efficient degradation of dyes in water. The combination of the two MOFs results in a significant enhancement of the surface open sites, optical responsivity range, and charge-separating efficiency through synergistic effects. In addition, the capture experiments conducted on the photocatalytic process have verified that ∙O₂⁻ and h⁺ are the primary active species. Consequently, CAU-17/MIL-100(Fe) exhibited excellent photocatalytic activity and stability. The degradation rate of the optimal CAU-17/MIL-100(Fe) photocatalyst was 34.55 times that of CAU-17 and 3.60 times that of MIL-100(Fe). Our work provides a new strategy for exploring the visible-light degradation of RhB in bimetallic MOF composites. Full article

The presence of organic dyes and heavy metal ions in water sources poses a significant threat to human health and the ecosystem. In this study, hydrogel adsorbents for water pollution remediation were synthesized using Guipi residue (GP), a cellulose material from Chinese herbal medicine, and chitosan (CTS) through radical polymerization with acrylamide (AM) and acrylic acid (AA). The characteristics of the hydrogels were analyzed from a physicochemical perspective, and their ability to adsorb was tested using model pollutants such as Pb²⁺, Cd²⁺, Rhodamine B (RhB), and methyl orange (MO). The outcomes revealed that GP/CTS/AA-co-AM, which has improved mechanical attributes, effectively eliminated these pollutants. At a pH of 4.0, a contact duration of 120 min, and an initial concentration of 600 mg/L for Pb²⁺ and 500 mg/L for Cd²⁺, the highest adsorption capabilities were 314.6 mg/g for Pb²⁺ and 289.1 mg/g for Cd²⁺. Regarding the dyes, the GP/CTS/AA-co-AM hydrogel displayed adsorption capacities of 106.4 mg/g for RhB and 94.8 mg/g for MO, maintaining a stable adsorption capacity at different pHs. Compared with other competitive pollutants, GP/CTS/AA-co-AM demonstrated a higher absorption capability, mainly targeted toward Pb²⁺. The adsorption processes for the pollutants conformed to pseudo-second-order kinetics models and adhered to the Langmuir models. Even after undergoing five consecutive adsorption and desorption cycles, the adsorption capacities for heavy metals and dyes remained above 70% and 80%. In summary, this study effectively suggested the potential of the innovative GP/CTS/AA-co-AM hydrogel as a practical and feasible approach for eliminating heavy metals and dyes from water solutions. Full article

The high-power lasers have important implications for present and future light-based technologies; therefore, the protection measures against their high-intensity radiation are extremely important. Currently, a great deal of interest is directed towards the development of new nonlinear optical materials for passive optical limiters, which are used to protect the human eye and sensitive optical and optoelectronic devices from laser-induced damage. Biopolymers doped with natural dyes are emerging as a new class of optical materials with interesting photosensitive properties. In this paper, the optical limiting capability of deoxyribonucleic acid bio-polymer functionalized with Turmeric natural dye has been demonstrated for the first time, to the best of our knowledge. The experimental investigation of the optical limit has been done by the Intensity-scan method in the NIR spectral domain at the important telecommunication wavelength of 1550 nm, using ultrashort laser pulses (~120 fs). Several optical properties of this natural dye are presented and discussed. The values of the optical transmittance in the linear regime, the saturation intensity of the nonlinear transmittance curves, and the coefficient of the nonlinear absorption have been determined. The influence of the DNA biopolymer and natural dye concentration on the optical limiting properties of the investigated biomaterials is reported and discussed. The photostability and thermal stability of the investigated solutions have also been evaluated by monitoring the temporal decay of the normalized absorption spectra under illumination with UVA light and heating, respectively. Our results evidence the positive influence of the DNA, which embeds Turmeric natural dye, on the optical limiting functionality itself and on the photostability and thermal stability of this novel material. The performed study reveals the potential of the investigated novel biomaterial for applications in nonlinear photonics, in particular in optical limiting. Full article

This study employs density functional theory (DFT) to evaluate the optoelectronic features of five natural dyes (cyanidin, delphinidin, pelargonidin, peonidin, and petunidin) in gas and ethanol phases for potential dye-sensitized solar cell (DSSC) applications. Calculations cover HOMO and LUMO energy levels, charge transfer potential gaps, and light absorption properties correlated with oscillator strengths. Photovoltaic aspects, including light-harvesting efficiency (LHE), electron injection efficiency (ΔG^inject), regeneration efficiency (ΔG^regen), open-circuit voltage (V_OC), excited-state lifetime (τ), and the electronic coupling constant (|V_RP|), were computed to assess DSSC suitability. DFT analysis reveals that cyanidin, delphinidin, and petunidin exhibit favorable LUMOs for efficient electron injection into the semiconductor’s conduction band. Cyanidin demonstrates a high quantum yield for light absorption. Delphinidin and petunidin act as effective light absorbers with high excitation energies and oscillator strengths, while petunidin and delphinidin display strong LHE, indicating excellent electron-donating capabilities. Peonidin shows promising ΔG^inject despite needing more energy for injection. Pelargonidin excels in ΔG^regen and |V_RP|, enhancing DSSC performance. Petunidin and delphinidin exhibit a high V_OC. Petunidin efficiently transmits energy through a large τ, while pelargonidin’s |V_RP| confirms its potential as a favorable sensitizer. In summary, each dye possesses unique properties, and understanding them aids in selecting the most suitable dye for enhanced DSSC performance. Full article