Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.137
Filtrar
1.
J Environ Sci (China) ; 148: 437-450, 2025 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-39095178

RESUMEN

For environmental applications, it is crucial to rationally design and synthesize photocatalysts with positive exciton splitting and interfacial charge transfer. Here, a novel Ag-bridged dual Z-scheme Ag/g-C3N4/CoNi-LDH plasmonic heterojunction was successfully synthesized using a simple method, with the goal of overcoming the common drawbacks of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers, and unstable structure. These materials were characterized by XRD, FT-IR, SEM, TEM UV-Vis/DRS, and XPS to verify the structure and stability of the heterostructure. The pristine LDH, g-C3N4, and Ag/g-C3N4/CoNi-LDH composite were investigated as photocatalysts for water remediation, an environmentally motivated process. Specifically, the photocatalytic degradation of tetracycline was studied as a model reaction. The performance of the supports and composite catalyst were determined by evaluating both the degradation and adsorption phenomenon. The influence of several experimental parameters such as catalyst loading, pH, and tetracycline concentration were evaluated. The current study provides important data for water treatment and similar environmental protection applications.


Asunto(s)
Nanocompuestos , Fotólisis , Plata , Contaminantes Químicos del Agua , Purificación del Agua , Nanocompuestos/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Plata/química , Catálisis , Nitrilos/química , Compuestos de Nitrógeno/química , Adsorción , Grafito
2.
Environ Res ; : 119721, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39096991

RESUMEN

The indiscriminate discharge of micropollutants (e.g., dyes, antibiotics, industrial additives, etc.) represents a significant risk to human health, and the removal of these substances from water bodies has become a prominent area of research within the field of environmental remediation. A simple hydrothermal-precipitation-photoreduction method was employed to synthesize novel Z-scheme heterojunction photocatalysts of AgBr/CoWO4/Ag. The catalysts demonstrated remarkable degradation capabilities with regard to a range of micropollutants present in wastewater. Of the catalysts tested, 5AgBr/CoWO4/Ag exhibited the highest degradation rates, reaching 98.58% for Rhodamine B, 86.82% for tetracycline hydrochloride, and 95.60% for 2-mercaptobenzothiazole within 60 minutes. In particular, the reaction kinetic rate of 5AgBr/CoWO4/Ag towards Rhodamine B degradation (k2 = 0.26278 L·mg-1·min-1) is 9 times that of AgBr (k2 = 0.02953 L·mg-1·min-1) and 113 times that of CoWO4 (k2 = 0.00233 L·mg-1·min-1), which serves to highlight the exceptional photocatalytic activity of the material. The experimental data and subsequent analysis indicated that the enhanced photocatalytic performance can be attributed to two factors: firstly, the electron mediation by Ag nanoparticles leading to improved charge separation efficiency, and secondly, the formation of Z-scheme heterojunctions between AgBr and CoWO4. The cyclic tests provided confirmation of the excellent stability and recyclability of the AgBr/CoWO4/Ag photocatalysts. It is anticipated that this study will facilitate the development of novel methods for the degradation of refractory micropollutants and provide insights into environmental remediation, thereby contributing to the sustainable development of society.

3.
Artículo en Inglés | MEDLINE | ID: mdl-39051551

RESUMEN

The generation of hydrogen through photocatalysis is a fascinating technology for addressing environmental concerns and the energy crisis. Nevertheless, the quest for cost-effective, stable, and efficient photocatalysts in the realm of energy conversion remains a significant challenge. Herein, we designed novel InVO4/Ti3C2 MXene (IVTC) heterostructures by employing acid etching to produce Ti3C2 MXene with an accordion-like morphology, using the hydrothermal technique for the production of orthorhombic InVO4 nanoparticles (NPs), and integrating them through a self-assembly approach. Both field-emission scanning electron microscopy and HRTEM analyses revealed a consistent distribution of InVO4 NPs with an average size of 43.4 nm on both surfaces and between the sheets of Ti3C2 MXene. The intimate interface between the Ti3C2 MXene nanosheet and InVO4 suppressed carrier recombination and promoted charge transfer, thereby boosting photocatalytic H2 production. Under visible light exposure, the rate of hydrogen evolution is enhanced in IVTC heterostructures containing an optimized 10% loading of InVO4, exhibiting over a 3-fold increase compared to pristine InVO4 NPs, maintaining efficiency across four cycles. This research presents a promising method for designing and creating high-efficiency heterostructures possessing excellent visible-light-driven photocatalytic activity for H2 evolution.

4.
Heliyon ; 10(13): e33354, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39040285

RESUMEN

A superficial, one step thermal polycondensation method has been employed for the manifestation of graphene like graphitic carbon nitride (g-C3N4) catalyst. The as synthesized g-C3N4 was well characterized by SEM and EDAX analysis, XRD, ATR-IR, FTIR, Fluorescence spectroscopy, Raman spectroscopy and UV-Visible spectroscopy which provide structural, morphological assemblage relating to the structure of g-C3N4. The g-C3N4 showed that an outstanding photochemical stability, morphology, conductive carbon framework and superior photocatalytic activity. The band gap value of g-C3N4 is 2.34 eV determined using Tauc plot. Due to low band gap (2.33 eV) and unique morphology which provides high separation and migration ability of the photogenerated charges, the g-C3N4 shows enhanced photocatalytic activity for the removal of many organic dyes such as Rhodamine B (RhB), Crystal Violet (CV), Methylene Blue (MB), Methyl Orange (MO), Naphthol Orange (NO) and a phenol derivative, p-Nitrophenol (p-NP). Among them, RhB dye was degraded almost 81 % at 90 min under sunlight irradiation in presence g-C3N4 while other dyes and p-NP was degraded at lower rate. From the experimental data, it was found that MO and p-NP degradation rate was least. The rate constant for degradation of Rh B is 1.1 × 10-2 min-1. Therefore, g-C3N4 can be used as an efficient photocatalyst for waste water treatment by the removal of such organic pollutants.

5.
ChemSusChem ; : e202301511, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39043608

RESUMEN

A photochemical method based on visible-light irradiation (blue LEDs/sunlight) has been developed for the intermolecular hydroamination and hydroetherification of electron-rich alkenes. This photochemical method is compatible with a wide range of azoles and electron-rich alkenes, such as vinyl ethers, vinyl sulfides and enamides, and is performed with low concentrations of photocatalyst (1000 ppm). Comprehensive mechanistic studies indicate that this process is initiated by the formation of an active radical cation intermediate through single electron oxidation of azole, which is mediated by excited Acr-Mes+ BF4-.

6.
Chemosphere ; 362: 142805, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38996979

RESUMEN

This study presents the green synthesis and multifunctional properties of Cu/NiO nanocomposites (NCs) fabricated with varying ratios (90:10, 80:20, and 70:30) using Commelina benghalensis leaf extract. X-ray diffraction (XRD) analysis confirmed the polycrystalline nature of the NCs, revealing crystallite sizes of 13.62, 13.22, and 7.14 nm. Scanning electron microscopy (SEM) showed rod-shaped and agglomerated particles with sizes ranging from 17.64 to 22.97 nm. Energy-dispersive X-ray spectroscopy (EDX) verified the elemental composition of copper, nickel, oxygen, and carbon. UV-visible spectroscopy determined the energy band gaps to be in the range of 1.24-1.56 eV. Fourier-transform infrared spectroscopy (FT-IR) indicated the presence of bioactive compounds responsible for the reduction of precursor metal salts. The Cu/NiO NCs exhibited remarkable antimicrobial activity, with the 90:10 ratio showing the highest zones of inhibition at 32.76 ± 0.23 mm, 18.66 ± 0.33 mm, and 14.36 ± 0.32 mm against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli, respectively. Additionally, the 70:30 Cu/NiO NCs demonstrated superior antioxidant activity, with a radical scavenging efficiency of 83.22%, closely approaching that of ascorbic acid (96.98%). Photocatalytic evaluations revealed that the NCs were highly effective in degrading environmental pollutants, achieving 97.69% degradation of malachite green and 96.52% of congo red under UV light irradiation. The novelty of this work lies in the use of Commelina benghalensis leaf extract as a sustainable and eco-friendly reducing and stabilizing agent for synthesizing Cu/NiO NCs, offering a green alternative to conventional methods. The synergistic effects between Cu and NiO in the different compositions (90:10, 80:20, and 70:30) enhanced the overall antimicrobial and photocatalytic activities, highlighting their potential for environmental remediation applications.

7.
Sci Rep ; 14(1): 16887, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39043803

RESUMEN

Wastewater treatment is inevitably required to alleviate the pollution of water resources by various contaminants such as antibiotics. MOFs are novel materials with photocatalytic activities. In this study, sonophotocatalytic degradation of tetracycline (TC) by the Cerium-based MOF (Ce-MOF) is optimized by modification of its synthesis route. Ce-MOF synthesis by room temperature (RT), hydrothermal (HT), and sonochemical synthesis (SC) are studied. TC degradation experiments revealed the superiority of SC synthesis. The interplay of main synthesis parameters, namely, initial ligand concentration, ultrasound (US) power and time on sonophotocatalytic activity of Ce-MOF, were investigated by response surface methodology model (RSM) utilizing the central composite experimental design (CCD). The optimum SC synthesis conditions are an initial ligand concentration of 8.4 mmol/L, a sonication power of 50 amplitude, and a US time of 60 min. The optimally synthesized Ce-MOF was characterized by infrared spectroscopy, FTIR, XRD, FE-SEM, TEM, zeta potential analysis, diffuse reflectance spectroscopy, particle size analysis, Mott-Schottky analysis, photocurrent analysis, electrochemical impedance spectra, and photoluminescence spectroscopy. The findings indicate that the removal efficiency of TC can reach up to 81.75% within 120 min in an aqueous solution containing an initial TC concentration of 120 ppm and 1 g/L Ce-MOF at pH of 7. Mineralization efficiency of the process is 71% according to COD measurements. The Ce-MOF catalyst retained its chemical stability and remained active upon TC degradation which makes it a promising candidate for wastewater treatment.

8.
Small ; : e2404622, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39058229

RESUMEN

Inspired by natural photosynthesis, the visible-light-driven Z-scheme system is very effective and promising for boosting photocatalytic hydrogen production and pollutant degradation. Here, a synergistic Z-scheme photocatalyst is constructed by coupling ReS2 nanosheet and ZnIn2S4 nanoflower and the experimental evidence for this direct Z-scheme heterostructure is provided by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance. Consequently, such a unique nanostructure makes this Z-scheme heterostructure exhibit 23.7 times higher photocatalytic hydrogen production than that of ZnIn2S4 nanoflower. Moreover, the ZnIn2S4/ReS2 photocatalyst is also very stable for photocatalytic hydrogen evolution, almost without activity decay even storing for two weeks. Besides, this Z-scheme heterostructure also exhibits superior photocatalytic degradation rates of methylene blue (1.7 × 10-2 min-1) and mitoxantrone (4.2 × 10-3 min-1) than that of ZnIn2S4 photocatalyst. The ultraviolet-visible absorption spectra, transient photocurrent spectra, open-circuit potential measurement, and electrochemical impedance spectroscopy reveal that the superior photocatalytic performance of ZnIn2S4/ReS2 heterostructure is mostly attributed to its broad and strong visible-light absorption, effective separation of charge carrier, and improved redox ability. This work provides a promising nanostructure design of a visible-light-driven Z-scheme heterostructure to simultaneously promote photocatalytic reduction and oxidation activity.

9.
J Colloid Interface Sci ; 675: 471-480, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38986320

RESUMEN

In addition to the intrinsic driving force of photocatalysis, the external thermal field from the photothermal effect can provide additional energy to the photo-catalytic system to improve the photo-catalytic hydrogen-evolution (PHE) efficiency. Herein, based on the results of density functional theory, we designed and constructed a hollow core-shell FeNi2S4@Mn0.3Cd0.7S (NFS@MCS) S-scheme heterojunction with a photothermal effect, thereby realising a significant enhancement of the PHE performance due to the thermal effect, S-scheme heterojunction and hollow core-shell morphology. As a light collector and heat source, the hollow NFS could absorb and convert photons into heat, resulting in the increased local temperature of photocatalyst particles. Moreover, the S-scheme charge path at the interface not only improved the carrier separation efficiency but also retained a higher redox potential. All these are favourable to increase the PHE activity. The PHE tests show that 0.5 %-NFS@MCS exhibits the highest PHE rate of 17.11 mmol·g-1·h-1, 7.7 times that of MCS. Moreover, through a combination of theoretical calculation and experimental evidence, the PHE mechanism of the NFS@MCS system is discussed and clarified in-depth.

10.
Environ Geochem Health ; 46(8): 302, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38990227

RESUMEN

In this study, a highly efficient CoFe2O4-anchored g-C3N4 nanocomposite with Z-scheme photocatalyst was developed by facile calcination and hydrothermal technique. To evaluate the crystalline structure, sample surface morphology, elemental compositions, and charge conductivity of the as-synthesized catalysts by various characterization techniques. The high interfacial contact of CoFe2O4 nanoparticles (NPs) with g-C3N4 nanosheets reduced the optical bandgap from 2.67 to 2.5 eV, which improved the charge carrier separation and transfer. The photo-degradation of methylene blue (MB) and rhodamine B (Rh B) aqueous pollutant suspension under visible-light influence was used to investigate the photocatalytic degradation activity of the efficient CoFe2O4/g-C3N4 composite catalyst. The heterostructured spinel CoFe2O4 anchored g-C3N4 photocatalysts (PCs) with Z-scheme show better photocatalytic degradation performance for both organic dyes. Meanwhile, the efficiency of aqueous MB and Rh B degradation in 120 and 100 min under visible-light could be up to 91.1% and 73.7%, which is greater than pristine g-C3N4 and CoFe2O4 catalysts. The recycling stability test showed no significant changes in the photo-degradation activity after four repeated cycles. Thus, this work provides an efficient tactic for the construction of highly efficient magnetic PCs for the removal of hazardous pollutants in the aquatic environment.


Asunto(s)
Cobalto , Compuestos Férricos , Azul de Metileno , Nanocompuestos , Rodaminas , Contaminantes Químicos del Agua , Cobalto/química , Compuestos Férricos/química , Catálisis , Nanocompuestos/química , Rodaminas/química , Contaminantes Químicos del Agua/química , Azul de Metileno/química , Fotólisis , Luz , Compuestos Inorgánicos de Carbono/química , Nitrilos/química , Procesos Fotoquímicos , Compuestos de Nitrógeno/química , Grafito
11.
J Phys Condens Matter ; 36(41)2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-38968934

RESUMEN

Titanium dioxide (TiO2) based photocatalysts have been widely used as a photocatalyst for the degradation of various persistent organic compounds in water and air. The degradation mechanism involves the generation of highly reactive oxygen species, such as hydroxyl radicals, which react with organic compounds to break down their chemical bonds and ultimately mineralize them into harmless products. In the case of pharmaceutical and pesticide molecules, TiO2and modified TiO2photocatalysis effectively degrade a wide range of compounds, including antibiotics, pesticides, and herbicides. The main downside is the production of dangerous intermediate products, which are not frequently addressed in the literature that is currently available. The degradation rate of these compounds by TiO2photocatalysis depends on factors such as the chemical structure of the compounds, the concentration of the TiO2catalyst, the intensity, the light source, and the presence of other organic or inorganic species in the solution. The comprehension of the degradation mechanism is explored to gain insights into the intermediates. Additionally, the utilization of response surface methodology is addressed, offering a potential avenue for enhancing the scalability of the reactors. Overall, TiO2photocatalysis is a promising technology for the treatment of pharmaceutical and agrochemical wastewater, but further research is needed to optimize the process conditions and to understand the fate and toxicity of the degradation products.


Asunto(s)
Plaguicidas , Procesos Fotoquímicos , Titanio , Titanio/química , Catálisis , Plaguicidas/química , Preparaciones Farmacéuticas/química , Luz
12.
Artículo en Inglés | MEDLINE | ID: mdl-39023728

RESUMEN

Perovskites are an emerging material with a variety of applications, ranging from their solar light conversion capability to their sensing efficiency. In current study, perovskite nanocrystals (PNCs) were designed using theoretical density functional theory (DFT) analysis. Moreover, the theoretically designed PNCs were fabricated and confirmed by various characterization techniques. The calculated optical bandgap from UV-Vis and fluorescence spectra were 2.15 and 2.05 eV, respectively. The average crystallite size of PNCs calculated from Scherrer equation was 15.18 nm, and point of zero charge (PZC) was obtained at pH 8. The maximum eosin B (EB) removal efficiency by PNCs was 99.56% at optimized conditions following first-order kinetics with 0.98 R2 value. The goodness of the response surface methodology (RSM) model was confirmed from analysis of variance (ANOVA), with the experimental F value (named after Ronald Fisher) of 194.66 being greater than the critical F value F0.05, 14, 14 = 2.48 and a lack of fit value of 0.0587. The Stern-Volmer equation with a larger Ksv value of 1.303710 × 10 6 for Pb2+ suggests its greater sensitivity for Pb2+ among the different metals tested.

13.
Small ; : e2402521, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39007284

RESUMEN

Polyaniline (PANI), a typical organic photocatalyst, has an adjustable structure and good stability, can be easily synthesized on a large scale, and is economical. PANI is doped with ions to regulate its internal structure and improve its photocatalytic performance. However, its photocatalytic performance is limited by the doping concentration and its intrinsic properties, hindering its further application. Herein, PANI films with a piezo-photocatalytic function are fabricated to improve photocatalytic performance and explore their self-powered environmental purification property. PANI/poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) sandwich films, with PVDF-HFP as the interlayer, are prepared by introducing a piezoelectric field into PANI photocatalysts, thereby achieving excellent piezo-photocatalytic performance. The as-fabricated piezo-photocatalyst degrades methyl orange at a rate of 91.2% after 60 min under magnetic stirring. Owing to the low Young's modulus of the all-organic catalyst, self-powered purification is realized using the PANI/PVDF-HFP film. Leaf surfaces are functionalized by loading the film in them for removing pollutants under sunlight and water flow. Thus, this study proposes a common strategy, wherein a piezoelectric interlayer is introduced to load the organic photocatalyst for preparing an all-organic piezo-photocatalyst. This piezo-photocatalyst can be easily recycled and responds to weak forces, realizing its application for self-powered environmental purification.

14.
Nanomaterials (Basel) ; 14(13)2024 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-38998684

RESUMEN

Cu2ZnSnSe4 (CZTSe) nanoparticles (NPs) were successfully synthesized via a solvothermal method. Their structural, compositional, morphological, optoelectronic, and electrochemical properties have been characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), UV-vis absorption spectroscopy, and electrochemical impedance spectroscopy (EIS) techniques. Porosimetry and specific surface area in terms of the Brunauer-Emmett-Teller (BET) technique have also been studied. XRD indicates the formation of a polycrystalline kesterite CZTSe phase. Raman peaks at 173 and 190 cm-1 confirm the formation of a pure phase. TEM micrographs revealed the presence of nanoparticles with average sizes of ~90 nm. A BET surface area of 7 m2/g was determined. The CZTSe NPs showed a bandgap of 1.0 eV and a p-type semiconducting behavior. As a proof of concept, for the first time, the CZTSe NPs have been used as a visible-light-driven photocatalyst to Congo red (CR) azo dye degradation. The nanophotocatalyst material under simulated sunlight results in almost complete degradation (96%) of CR dye after 70 min, following a pseudo-second-order kinetic model (rate constant of 0.334 min-1). The prepared CZTSe was reusable and can be repeatedly used to remove CR dye from aqueous solutions.

15.
Int J Mol Sci ; 25(13)2024 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-38999979

RESUMEN

This study presents a pioneering synthesis of a direct Z-scheme Y2TmSbO7/GdYBiNbO7 heterojunction photocatalyst (YGHP) using an ultrasound-assisted hydrothermal synthesis technique. Additionally, novel photocatalytic nanomaterials, namely Y2TmSbO7 and GdYBiNbO7, were fabricated via the hydrothermal fabrication technique. A comprehensive range of characterization techniques, including X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV-visible spectrophotometry, X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray energy-dispersive spectroscopy, fluorescence spectroscopy, photocurrent testing, electrochemical impedance spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance, was employed to thoroughly investigate the morphological features, composition, chemical, optical, and photoelectric properties of the fabricated samples. The photocatalytic performance of YGHP was assessed in the degradation of the pesticide acetochlor (AC) and the mineralization of total organic carbon (TOC) under visible light exposure, demonstrating eximious removal efficiencies. Specifically, AC and TOC exhibited removal rates of 99.75% and 97.90%, respectively. Comparative analysis revealed that YGHP showcased significantly higher removal efficiencies for AC compared to the Y2TmSbO7, GdYBiNbO7, or N-doped TiO2 photocatalyst, with removal rates being 1.12 times, 1.21 times, or 3.07 times higher, respectively. Similarly, YGHP demonstrated substantially higher removal efficiencies for TOC than the aforementioned photocatalysts, with removal rates 1.15 times, 1.28 times, or 3.51 times higher, respectively. These improvements could be attributed to the Z-scheme charge transfer configuration, which preserved the preferable redox capacities of Y2TmSbO7 and GdYBiNbO7. Furthermore, the stability and durability of YGHP were confirmed, affirming its potential for practical applications. Trapping experiments and electron spin resonance analyses identified active species generated by YGHP, namely •OH, •O2-, and h+, allowing for comprehensive analysis of the degradation mechanisms and pathways of AC. Overall, this investigation advances the development of efficient Z-scheme heterostructural materials and provides valuable insights into formulating sustainable remediation strategies for combatting AC contamination.


Asunto(s)
Luz , Toluidinas , Catálisis , Toluidinas/química , Fotólisis , Contaminantes Químicos del Agua/química , Procesos Fotoquímicos , Espectroscopía de Fotoelectrones , Gadolinio/química
16.
Front Chem ; 12: 1425306, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39006489

RESUMEN

Stacking engineering is a popular method to tune the performance of two-dimensional materials for advanced applications. In this work, Jansu MoSSe and WSSe monolayers are constructed as a van der Waals (vdWs) heterostructure by different stacking configurations. Using first-principle calculations, all the relaxed stacking configurations of the MoSSe/WSSe heterostructure present semiconductor properties while the direct type-II band structure can be obtained. Importantly, the Z-scheme charge transfer mode also can be addressed by band alignment, which shows the MoSSe/WSSe heterostructure is an efficient potential photocatalyst for water splitting. In addition, the built-in electric field of the MoSSe/WSSe vdWs heterostructure can be enhanced by the S-Se interface due to further asymmetric structures, which also results in considerable charge transfer comparing with the MoSSe/WSSe vdWs heterostructure built by the S-S interface. Furthermore, the excellent optical performances of the MoSSe/WSSe heterostructure with different stacking configurations are obtained. Our results provide a theoretical guidance for the design and control of the two-dimensional heterostructure as photocatalysts through structural stacking.

17.
Adv Mater ; : e2403153, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39039977

RESUMEN

Atomically dispersed active sites in a photocatalyst offer unique advantages such as locally tuned electronic structures, quantum size effects, and maximum utilization of atomic species. Among these, asymmetric atomic dual-sites are of particular interest because their asymmetric charge distribution generates a local built-in electric potential to enhance charge separation and transfer. Moreover, the dual sites provide flexibility for tuning complex multielectron and multireaction pathways, such as CO2 reduction reactions. The coordination of dual sites opens new possibilities for engineering the structure-activity-selectivity relationship. This comprehensive overview discusses efficient and sustainable photocatalysis processes in photocatalytic CO2 reduction, focusing on strategic active-site design and future challenges. It serves as a timely reference for the design and development of photocatalytic conversion processes, specifically exploring the utilization of asymmetric atomic dual-sites for complex photocatalytic conversion pathways, here exemplified by the conversion of CO2 into valuable chemicals.

18.
Artículo en Inglés | MEDLINE | ID: mdl-39042192

RESUMEN

The presence of metronidazole (MNZ) and acetaminophen (ACE) in aquatic environments has raised growing concerns regarding their potential impact on human health. Incorporating various patterns into a photocatalytic material is considered a critical approach to achieving enhanced photocatalytic efficiency in the photocatalysis process. In this study, WO3 nanoparticles, which were immobilized onto ferromagnetic multi-walled carbon nanotubes that were functionalized using (3-glycidyloxypropyl)trimethoxysilane (FMMWCNTs@GLYMO@WO3), exhibited remarkable efficiency in removing MNZ and ACE (93% and 97%) in only 15 min. In addition, the new visible-light FMMWCNTs@GLYMO@WO3 nanoparticles as a magnetically separable photocatalyst were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), EDS-mapping, vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), diffuse reflectance spectroscopy (DRS), high-performance liquid chromatography (HPLC), and total organic carbon (TOC) due to detailed studies (morphological, structural, magnetic and optical properties) of the photocatalyst. In-depth spectroscopic and microscopic characterization of the newly developed ferromagnetic FMMWCNTs@GLYMO@WO3 (III) photocatalyst revealed a spherical morphology, with nanoparticle diameters averaging between 23 and 39 nm. Compared to conventional multiwall carbon nanotube and WO3 photocatalysts, FMMWCNTs@GLYMO@WO3 (III) demonstrated superior photocatalytic activity. Remarkably, it exhibited excellent reusability, maintaining its efficiency over a minimum of five cycles in the degradation of metronidazole (MNZ) and acetaminophen (ACE).

19.
Artículo en Inglés | MEDLINE | ID: mdl-38992302

RESUMEN

The world is dealing with unprecedented environmental challenges, leading to a growing urgency to limit environmental damage. So, this study focuses on the synthesis of pure CuO, Zn, Ce, and Zn/Ce dual-doped CuO nanoparticles (NPs) using extract of Citrus limon leaves as reductant via simple co-precipitation method. The X-ray diffraction (XRD) characterization was employed to analyze structural characteristics of synthesized samples which confirm influence of Zn or Ce doping on crystallite size, dislocation density, and strain. The role of functional groups, changes in force constant, and bond length on addition of dopants was indicated by FTIR results. The SEM and TEM results showed variation in morphology from irregular to spherical. The zeta-potential and BET analysis confirmed surface potential as well as surface area characteristics. The change in energy gap values from 1.81 to 1.45 eV of Zn/Ce-doped CuO NPs computed from UV-vis analysis elevated its photocatalytic performance and reduced the chances of recombination of electron-hole pair due to presence of trapping levels between valence and conduction bands. The enhanced photo-degradation of Congo red (CR) and rhodamine B (RhB) with 91 and 94%, respectively, for Zn/Ce-doped CuO NPs was observed. The so-obtained samples have also exhibited good antibacterial and antioxidant activities.

20.
Small ; : e2403743, 2024 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-38973074

RESUMEN

Photocatalytic hydrogen peroxide production from water and oxygen offers a clean and sustainable alternative to the conventional energy-intensive anthraquinone oxidation method. Compared to powdered covalent triazine frameworks (CTFs), the film morphology of CTFs provides better connectivity in 2D, yielding several advantages: more efficient connections between active sites, reduced electron-hole pair recombination, increased resistance to superoxide radical induced corrosion, and decreased light scattering. Leveraging these benefits, it has incorporated dual active sites for both the oxygen reduction reaction (ORR) and the water oxidation reaction (WOR) into a CTF film system. This dual-active CTF film demonstrated an exceptional hydrogen peroxide production rate of 19 460 µmol h⁻¹ m⁻2 after 1 h and 17 830 µmol h⁻¹ m⁻2 after 5 h under visible light irradiation (≥420 nm) without the need for sacrificial agents.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA