Search Results (2,514)

In this explorative work, molybdenum trioxide (MoO₃) and representative doped MoO₃ materials, i.e., Cu-doped MoO₃ (2% Cu, “Cu-MoO₃”) and H-doped MoO₃ (H_0.31MoO₃, “H-MoO₃”), have been tested for the first time as photocatalysts in the UV-vis light-driven depolymerization of lignin. The catalysts have been characterized by XRD, TEM, ATR-FTIR, and UV-vis DRS. Under the adopted conditions (UV-vis irradiation, solvent 0.01 M aqueous NaOH, lignin 200 ppm, catalyst 1 g/L, rt, 5 h), photocatalytic depolymerization of wheat-straw lignin (WSL) produced increasing amounts of bio-oil on changing the catalyst from pristine MoO₃ to Cu-MoO₃ and H-MoO₃ (23%, 28% and 30%, respectively). Also, quantification of vanillin and vanillic acid shows a similar increasing trend. These results appear in line with the estimated band gap energies, which decrease in the order: MoO₃ (2.91 eV) > Cu-MoO₃ (2.86 eV) > H-MoO₃ (2.77 eV). H-MoO₃ shows the best catalytic performance, which was then fruitfully explored in the photocatalytic depolymerization of benchmark commercial Kraft lignin (bio-oil yield 32%, vanillin and vanillic acid yields 1.28% and 0.78%, respectively). In view of the results obtained, this work is expected to provide new ideas for the design of heterogeneous photocatalytic system for lignin cleavage. Full article

Recent advancements in nanotechnology and materials science have enabled the development of magnetic photocatalysts with improved efficiency, stability, and reusability, offering a promising approach for wastewater treatment. The integration of magnetic nanoparticles (MNPs) into photocatalytic processes has gained significant attention as a sustainable method for addressing emerging pollutants—such as antibiotics and pharmaceutical compounds—which pose environmental and public health risks, including the proliferation of antibiotic resistance. Surface modification techniques, specifically applied to MNPs, are employed to enhance their photocatalytic performance by improving surface reactivity, reducing nanoparticle agglomeration, and increasing photocatalytic activity under both visible and ultraviolet (UV) light irradiation. These modifications also facilitate the selective adsorption and degradation of target contaminants. Importantly, the modified nanoparticles retain their magnetic properties, allowing for facile separation and reuse in multiple treatment cycles via external magnetic fields. This review provides a comprehensive overview of recent developments in surface-modified MNPs for wastewater treatment, with a focus on their physicochemical properties, surface modification strategies, and effectiveness in the removal of antibiotics from aqueous environments. Furthermore, the review discusses advantages over conventional treatment methods, current limitations, and future research directions, emphasizing the potential of this technology for sustainable and efficient water purification. Full article

Porous photocatalysts from agricultural waste, i.e., apricot and peach shell, with titanium dioxide were prepared by a carbonaceous method, the adsorption and photocatalytic degradation and its kinetics about methylene blue (MB) were studied systematically. The properties of the prepared composite sorbents were characterized using Brunauer–Emmett–Teller, surface area, scanning electron microscopy, and energy dispersive spectroscopy analyses. Several key factors, including radiation, pH, temperature, initial MB concentration, contact time, and sorbent dosage, as well as photocatalytic activity were investigated. All the waste-TiO₂ adsorbents showed improved adsorption and photodegradation performance compared to commercial charchoal-TiO₂. The produced materials presented high specific surface areas especially those derived from apricot shell-TiO₂ with a combination of type I and IV adsorption isotherms with a hysteresis loop indicating micro and mesopore structures. In addition, under UV radiation, the composite sorbents exhibited greater MB removal efficiency than non-radiated composite sorbents. The examined conditions have shown the best MB adsorption results at pH greater than 7.5, temperature 30 °C, contact time 120 min, initial concentration 0.5 mg/L MB, and sorbent dosage equal to 2.0 g/L C/MB. The total removal rate of MB is 98.5%, while the respective amount of commercial charcoal-TiO₂ is equal to 75.0%. The kinetic model that best describes the experimental data of MB degradation from the photocatalytic materials is the pseudo-second order model. In summary, this work highlights the effectiveness and feasibility of transforming agricultural waste into carbonaceous composite sorbent for the removal of cationic dyes from wastewater. Future work will involve scaling up the synthesis of the catalyst and evaluating its performance using bed reactors for industrial processes. Full article

Natural zeolites—clinoptilolite from Golobradovo and mordenite from Lyaskovets deposits, Bulgaria—were used for the preparation of zeolite-supported CeO₂@Polybenzimidazole (PBI) hybrid materials, incorporating green-synthesized ceria using Veronica officinalis L extract. In order to prepare the hybrid composites, the zeolites/CeO₂ were surface-impregnated with an ethanolic KOH solution of meta-PBI, which served as a dispersant medium. The composites were investigated by WDXRF, PXRD, FTIR, POM, and TG. The materials were tested in the photocatalytic degradation of 5 ppm Reactive Black 5 dye under UV light. The higher degree of degradation (98%) was achieved using mordenite/CeO₂@PBI as the photocatalyst compared to the clinoptilolite/CeO₂@PBI (14%). Full article

Modulating the electronic structure and surface properties of graphitic carbon nitride (g-C₃N₄) by chemically phosphorus doping is an effective strategy for improving its photocatalytic performance. However, in order to benefit from practical applications, the cost-effectiveness, efficiency, and optimization of the doping level need to be investigated further. Herein, we report a structural doping of P into g-C₃N₄ by in situ polymerization of the mixture of dicyandiamide (DCDA) and phosphorus pentoxide (P₂O₅). As an alternative to previous studies that used complex organic phosphorus precursors or post-treatment strategies, this work proposed a one-pot thermal polycondensation method that is low-cost, scalable, and enables controlled phosphorus substitutions at carbon sites of the g-C₃N₄ heptazine structure. Most of the structural features of g-C₃N₄ were well retained after doping, but the electronic structures and light harvesting capacity had been effectively altered, which provided not only a much better charge separation but also an improvement in photocatalytic activity toward H₂ evolution under irradiation of a simulated sunlight. The optimized sample with P-doping content of 9.35 at.% (0.5PGCN) exhibited an excellent photocatalytic performance toward H₂ evolution, which is over 5 times higher than that of bulk g-C₃N₄. This work demonstrates a facile one-step in situ route for producing high-yield photocatalysts using low-cost commercial precursors, offering practical starting materials for studies in solar cells, polymer batteries, and photocatalytic applications. Full article

Silicon carbide (SiC) has emerged as a robust and tunable semiconductor for advanced photocatalytic applications. This review provides a comprehensive overview of recent progress in the development of SiC-based materials for environmental remediation and solar-driven hydrogen production. Key aspects discussed include morphological engineering, heterostructure design, doping strategies, and plasmonic enhancement. Emphasis is placed on structure–activity relationships, insights from density functional theory (DFT) and machine learning (ML) models, and synergistic effects in composite systems. This review concludes with a critical analysis of current challenges and future research directions, highlighting the potential of SiC implementation as a sustainable platform for next-generation photocatalytic technologies. Full article

TiO₂ shows improved photocatalytic properties when combined with other oxides, such as ZrO₂. Unfortunately, this material does not exhibit a spectral response in the visible range, but this can be improved by adding WO₃. Here, the effect of the amount of WO₃ and the treatment temperature on TiO₂-ZrO₂-WO₃ materials applied in the solar photocatalytic oxidation of sildenafil was evaluated. The materials were synthesized using the sol–gel method and were characterized by N₂, XRD, UV-Vis RDS, SEM, PL, and XPS. Photocatalytic activity was determined by the degradation and mineralization of sildenafil. The most active photocatalysts were selected for stability testing and to determine the oxidizing species that dominate the reaction mechanism. The optimal amount of WO₃ that improves solar photocatalytic activity at both treatment temperatures was found to be 1% with a reaction mechanism based on OH· and h⁺. WO₃ reduces electron–hole pair recombination. At 500 °C, the crystallinity of the anatase phase is improved, while at 800 °C, the transformation to rutile is suppressed at low WO₃ concentrations. XPS observed the reduction in Ti⁴⁺ to Ti³⁺ and W⁶⁺ to W⁵⁺ in TiO₂–ZrO₂–WO₃ materials, which were found to be photoactive under sunlight with potential for use in industrial-scale reaction systems. Full article

Designing and constructing heterojunctions has emerged as a pivotal strategy for improving the photocatalytic efficiency of semiconductors. In this study, we report the controlled synthesis of an Au/Zn₃In₂S₆ Schottky junction through a combination of hydrothermal and in situ photodeposition methods. The structural, morphological, and photoelectrochemical properties of the catalyst were meticulously characterized using a suite of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoelectrochemical (PEC) measurements, and electron spin resonance (ESR) spectroscopy. The optimized 3% Au/Zn₃In₂S₆ composite exhibited a remarkable enhancement in both photocatalytic activity and stability, achieving a 90.4% removal of bisphenol A (BPA) under UV–visible light irradiation within 100 min. The corresponding first-order reaction rate constant was approximately 1.366 h⁻¹, nearly 4.37 times greater than that of the pristine Zn₃In₂S₆. This substantial improvement can be attributed to several key factors, including increased BPA adsorption, enhanced light absorption, and the efficient charge separation facilitated by the Au/Zn₃In₂S₆ heterojunction. Photogenerated holes, superoxide radicals, and hydroxyl radicals were identified as the primary reactive species responsible for the BPA degradation. This work highlights the potential of metal-modified semiconductors for advanced photocatalytic applications, offering insights into the design of highly efficient materials for environmental remediation. Full article

Photocatalysis driven by the visible light of solar energy has received considerable attention in the field of environmental remediation and clean energy production. In this work, monomeric sulfonated palladium phthalocyanine (PdPcS) was encapsulated in zeolitic imidazolate frameworks-8 (ZIF-8) crystals (denoted PdPcS@ZIF-8) through electrostatic interaction in the ammonia system, while their photocatalytic activity was well-maintained together with the structural regularity of ZIF-8 crystals. For comparison, a PdPcS/ZIF-8 sample was obtained from the traditional impregnation method. The ¹³C NMR and UV-DRS spectra confirmed the difference between PdPcS@ZIF-8 and PdPcS/ZIF-8 in terms of the chemical environment effect for PdPcS. Under visible light, the optimal PdPcS@ZIF-8 catalyst achieved complete degradation of 0.1 mM bisphenol A in 120 min. It also exhibited excellent stability, retaining 81.5% activity after four cycles, far outperforming the impregnated sample (32.5%) due to effective encapsulation preventing PdPcS leaching. This versatile one-step synthetic strategy is expected to be useful for designing novel macromolecules@MOF composite materials. Full article

The increasing discharge of recalcitrant organic dyes from the textile industry necessitates the development of efficient and sustainable wastewater treatment technologies. This study reports the successful eco-friendly fabrication of magnetically separable cerium–manganese ferrite (Ce-MnFe₂O₄) nanocatalysts via a one-pot green synthesis route, utilizing an aqueous extract of Brachychiton populneus leaves. The structural, morphological, magnetic, and optical properties of the synthesized nanocatalysts were systematically investigated. X-ray diffraction (XRD) analysis confirmed the formation of a phase-pure cubic spinel structure, with evidence of Ce³⁺ ion incorporation leading to lattice expansion and the formation of beneficial oxygen vacancies. The composite material exhibited superparamagnetic behavior with a high saturation magnetization of 38.7 emu/g, which facilitates efficient magnetic separation and recovery. Optical studies revealed a direct bandgap of 2.33 eV, enabling significant photocatalytic activity under visible light irradiation. The Ce-MnFe₂O₄ nanocatalyst demonstrated superior performance, achieving degradation efficiencies of 96% for methylene blue and 98% for Congo Red within 90 min. Furthermore, the catalyst demonstrated good operational stability, maintaining 62% of its initial degradation efficiency for CR and 51% for MB after five consecutive reuse cycles. These results underscore the potential of this green-synthesized, magnetically recoverable nanocatalyst as a highly effective and sustainable solution for the remediation of dye-contaminated industrial effluents. Full article

Deep eutectic solvents are a sustainable and chemically tunable class of solvents formed by strong hydrogen bonding between a hydrogen bond acceptor and a hydrogen bond donor. Their extreme versatility has established deep eutectic solvents in ten key applied areas, including the green extraction of bioactive compounds, CO₂ capture, electrochemistry, and the catalytic media. Research is shifting towards highly innovative frontier trends, such as the role of deep eutectic solvents in dynamic covalent chemistry and as templates for advanced photocatalytic nanomaterials. Other innovative directions include artificial organelles for bioremediation, thermoacoustic deep eutectic solvents for smart drug delivery, and their use as multifunctional interfaces for 2D materials. The future of deep eutectic solvents lies in process engineering and scale-up, supported by computational chemistry, confirming their position as a central pillar of the circular economy. This trajectory marks the transition of deep eutectic solvents from laboratory curiosities to a scalable industrial reality. Full article

Cadmium sulfide is an important II-VI semiconductor known for its valuable photocatalytic properties ascribable to its band gap energy, which allows light absorption in the visible domain. Nonetheless, the application of cadmium sulfide in wastewater organic pollutant degradation is restricted due to its high toxicity to humans, soil, and marine life. To address this issue, we developed new composite materials by depositing CdS on a bentonite support in a 1:9 mass ratio to develop a photocatalyst with lower toxicity. In the first step, bentonite was activated using an aqueous HCl solution; for the deposition of CdS powder, we proposed the trituration method and compared it with chemical precipitation and hydrothermal synthesis, using thioacetamide as a sulfide ion source. The modified bentonite underwent characterization using X-ray diffraction, scanning electron microscopy, X-ray fluorescence, UV-Vis, and FTIR spectroscopy. The photocatalytic activity was tested in the degradation of Congo red (CR), a persistent diazo dye. The efficiency of removing CR with CdS–bentonite composites depended on the deposition method of CdS, and it was higher than that of pristine CdS and of only adsorption onto acid-activated bentonite. The photocatalytic degradation mechanism was estimated by the scavenger test using ethylenediaminetetraacetic acid disodium salt, ascorbic acid, ethanol, and silver nitrate as radical scavengers. Full article

Metalloporphyrin-based covalent organic frameworks (MPor-COFs) are emerging porous crystalline materials that combine the optoelectronic properties of metalloporphyrins with the highly ordered structure of COFs. Such a combination not only extends the light absorption spectrum of COFs by incorporating porphyrins but also improves the separation and transport capabilities of photo-generated electrons and holes by leveraging the structural advantages of organic frameworks. At the same time, the metal ions embedded in the porphyrin ring provide abundant active sites and optimize charge transfer channels, showing particular advantages in photocatalysis. The molecular design, construction, and photocatalytic application of MPor-COFs were reviewed in this paper. The intrinsic relationship among the structure, optoelectronic properties, and specific photocatalytic application received special attention. First, the role of the metal center in regulating the electronic structure and photophysical property of porphyrin monomers was introduced, as well as the impact of bond type on framework stability and charge transport efficiency. Then, the synthesis strategies for MPor-COFs were summarized. Finally, the applications of these materials in photocatalysis were critically reviewed, and their prospects and challenges in energy conversion and environmental remediation were also discussed. Full article

This research reports the development of photocatalytic active composites for hydrogen evolution obtained through high-energy mechanical milling of a mixture of the organic semiconductor g-C₃N₄ (CN) and the metal–organic framework ZIF-67. These composites, called CNZ-x (X = mass proportion of ZIF-67), were characterized using powder XRD, which showed that the crystalline phases of both the g-C₃N₄ and ZIF-67 precursors are present in the composites. SEM was used to determine the morphology, revealing that the ZIF-67 octahedral particles adhere to the surface of the CN sheets due to the intimate interfacial contact induced by high-energy mechanical grinding. The results of the photocatalytic evolution of H₂ indicate that the CNZ-50 composite produced 261 μmol g⁻¹ of H₂, which is higher than the 229.5 and 124 μmol g⁻¹ produced by the precursors ZIF-67 and CN, respectively. The higher efficiency in H₂ evolution is due to the composite having better electron-hole separation than the precursor materials. Full article

The oxidation of chlorophenolic compounds is essential for converting these persistent and toxic pollutants into less harmful products, thereby reducing their environmental and health impacts. In this study, a p-coumaric acid ester derivative was employed as the starting material to synthesize the corresponding phthalonitrile precursor (EnCA-CN), followed by the preparation of non-peripherally substituted Co(II) and Cu(II) phthalocyanine complexes (EnCA-Copc and EnCA-CuPc). These complexes were subsequently characterized using a range of spectroscopic techniques and designed to engage in π–π interactions with graphitic carbon nitride to form efficient photocatalytic materials. The structures of the two effective catalysts were characterized by FT-IR, SEM, and XRD analyses, after which their photocatalytic performance and recyclability in the degradation of 2-chlorophenol, 2,3-dichlorophenol, and 2,3,6-trimethylphenol were evaluated. The optimum catalyst loading for the MPc/g-C₃N₄ composites was determined to be 0.5 g/L, yielding the highest photocatalytic efficiency. The EnCA-CoPc/g-C₃N₄ catalyst achieved 90.8% product selectivity and 82.6% conversion in the oxidation of 2-chlorophenol, whereas the EnCA-CuPc/g-C₃N₄ catalyst exhibited approximately 80.0% pollutant removal. The degradation efficiencies followed the order 2-CP > 2,3-DCP > 2,3,6-TCP, with benzoquinone derivatives identified as the major oxidation products. In recyclability tests, both catalysts retained more than 50% of their activity after five cycles; EnCA-CoPc/g-C₃N₄ maintained 68% conversion in the 5th cycle, while EnCA-CuPc/g-C₃N₄ retained 60% conversion in the 4th cycle. Full article