Effects of polymer network flexibility on the kinetics of DEZ vapor phase infiltration into photo-polymerized polyacrylates

Vapor phase infiltration (VPI) enables the fabrication of novel organic-inorganic hybrid materials with distinctive properties by infiltrating polymers with inorganic species through a top-down approach. However, understanding the process kinetics is challenging due to the complex interplay of sorption, diffusion and reaction processes. This study examines how polymer network flexibility affects the kinetics of diethylzinc (DEZ) infiltration into a highly crosslinked polyacrylate copolymer system composed of two monomers: trimethylolpropane triacrylate (TMPTA) and ethoxylated trimethylolpropane triacrylate (ETPTA). The findings show that increasing the ratio of ETPTA, which enhances network flexibility, facilitates precursor diffusion, resulting in deeper infiltration and faster saturation. A reaction-diffusion transport model is employed to qualitatively interpret the experimental results and gain insights into the underlying process mechanisms, thus contributing to a better understanding of VPI kinetics.

Biomass-derived substrate hydrogenation over rhodium nanoparticles supported on functionalized mesoporous silica

The use of supported rhodium nanoparticles (RhNPs) is gaining attention due to the drive for better catalyst performance and sustainability. Silica-based supports are promising for RhNP immobilization because of their thermal and chemical stability. Functionalizing silica allows for the design of catalysts with improved activity for biomass transformations. In this study, we synthesized rhodium nanoparticles (RhNPs) supported on N-functionalized silica-based materials, utilizing SBA-15 as the support and functionalizing it with either nicotinamide or an imidazolium-based ionic liquid. Solid-state 29Si and 13C NMR experiments confirmed successful ligand anchoring onto the silica surface. RhNPs@SBA-15-Imz[NTf2] and RhNPs@SBA-15-NIC were efficiently prepared and extensively characterized, revealing small, spherical, and well-dispersed fcc Rh nanoparticles on the support surface, confirmed by XPS analyses detecting metallic rhodium, Rh(I), and Rh(III) species. The catalytic performance of these materials is assessed in the hydrogenation of biomass-derived substrates, including furfural, levulinic acid, terpenes, vanillin, and eugenol, among others, underscoring their potential in sustainable chemical transformations. The nanocatalysts demonstrated excellent recyclability and resistance to metal leaching over multiple cycles. The study shows that neutral and ionic silica grafting fragments differently stabilize RhNPs, affecting their morphology, size, and interaction with silanol groups, which impacts their catalytic activity.

Tunable electronic structure and excellent catalytic properties of transition-metal-doped BeN4 monolayer

The electronic properties and OER catalytic activity of pristine BeN4 monolayers and single-transition-metal-doped BeN4 monolayers (TM@BeN4) were systematically investigated using density functional theory. Among all the types of TM@BeN4 analyzed, Fe@BeN4 was determined to exhibit the best OER activity, with an overpotential of 0.33 V, and to display excellent metallic conductivity. Besides, the OER catalytic activity of Fe@BeN4 can be further enhanced by applying biaxial strain and designing X-Fe@BeN4 (X = B, C, O, P, S) catalysts.

A new mesoporous Ce-Mn-LDH-based Co-MOF nano-composite for the green synthesis of tetrazoloquinazolines

Tannic acid (TA), as a plant polyphenol, has many active sites for chelation with metals, so TA-oligomers (TA-Olig) were used for the first time as ligands on the surface of Ce-Mn-LDH to prepare the layered double hydroxide-based metal-organic framework (Ce-Mn-LDH@CPTMS@TA-Olig@Co-MOF = E) nanocomposite. In this regard, a homogeneous water/ethanol solution was prepared by sol-gel method using polyethylene glycol and ammonia solution, and then TA was converted into a set of oligomers in the presence of formaldehyde. In the next step, Ce-Mn-LDH was prepared in a ratio of 1 : 4 of Ce to Mn, modified with 3-chloropropylmethoxysilane, functionalized by TA-Olig, and then cobalt salt was used to prepare E. Finally, the structure of E was determined by FT-IR, ICP, XRD, BET, EDX, SEM, SEM-mapping, TEM, and TGA-DTA techniques and used as a new and potent nanocatalyst for the synthesis of tetrazoloquinazolines a(1-12). One of the advantages of this nanocatalyst is the active surface to form products in a limited time in mild conditions with high efficiency and easy separation. Also, the catalytic activity is maintained even after four consecutive runs.

Magnetic hollow fibers of covalent organic frameworks (COF) for pollutant degradation and adsorptive removal

The shaping of covalent organic frameworks (COFs) from non-processible powder forms into applicable architectures with additional functionality remains a challenge. Using pre-electrospun polymer fibers as a sacrificial template, herein, we report a green synthesis of an architecture in the form of COF hollow fibers with an inner layer of peroxidase-like iron oxide nanoparticles as a catalytic material. When compared to peroxidase-like pristine iron oxide nanoparticles, these COF hollow fibers demonstrate higher catalytic breakdown of crystal violet due to their peroxidase-like activity via advanced oxidation process. Furthermore, as a potential adsorbent, hollow COF fibers exhibit significantly effective adsorption capacity and removal efficiency of organic solvent and oil from water. Because of their magnetic nature, COF hollow fibers can be easily recovered and have exhibited high recycling stability for both catalytic dye degradation and organic solvent removal from water.

Central Countries' and Brazil's Contributions to Nanotechnology

Abstract:

Nanotechnology is a cornerstone of the scientific advances witnessed over the past few years. Nanotechnology applications are extensively broad, and an overview of the main trends worldwide can give an insight into the most researched areas and gaps to be covered. This document presents an overview of the trend topics of the three leading countries studying in this area, as well as Brazil for comparison. The data mining was made from the Scopus database and analyzed using the VOSviewer and Voyant Tools software. More than 44.000 indexed articles published from 2010 to 2020 revealed that the countries responsible for the highest number of published articles are The United States, China, and India, while Brazil is in the fifteenth position. Thematic global networks revealed that the standing-out research topics are health science, energy, wastewater treatment, and electronics. In a temporal observation, the primary topics of research are: India (2020), which was devoted to facing SARS-COV 2; Brazil (2019), which is developing promising strategies to combat cancer; China (2018), whit research on nanomedicine and triboelectric nanogenerators; the United States (2017) and the Global tendencies (2018) are also related to the development of triboelectric nanogenerators. The collected data are available on GitHub. This study demonstrates the innovative use of data-mining technologies to gain a comprehensive understanding of nanotechnology's contributions and trends and highlights the diverse priorities of nations in this cutting-edge field.

Thiophene-Based Covalent Triazine Frameworks as Visible-Light-Driven Heterogeneous Photocatalysts for the Oxidative Coupling of Amines

This study reports on a metal-free Covalent Triazine Framework (CTF) incorporating bithiophene structural units (TP-CTF) with a semicrystalline structure as an efficient heterogeneous photocatalyst under visible light irradiation. The physico-chemical properties and composition of this material was confirmed via different characterization solid-state techniques, such as XRD, TGA, CO2 adsorption and FT-IR, NMR and UV-Vis spectroscopies. The compound was synthesized through a solvothermal process and was explored as a heterogeneous photocatalyst for the oxidative coupling of amines to imines under visible light irradiation. TP-CTF demonstrated outstanding photocatalytic activity, with high conversion rates and selectivity. Importantly, the material exhibited exceptional stability and recyclability, making it a strong candidate for sustainable and efficient imine synthesis. The low bandgap of TP-CTF enabled the efficient absorption of visible light, which is a notable advantage for visible-light-driven photocatalysis.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.

Metal-Organic Frameworks Marry Sponge: New Opportunities for Advanced Water Treatment

Metal-organic frameworks (MOFs) have garnered attention across various fields due to their noteworthy features like high specific surface area, substantial porosity, and adjustable performance. In the realm of water treatment, MOFs exhibit great potential for eliminating pollutants such as organics, heavy metals, and oils. Nonetheless, the inherent powder characteristics of MOFs pose challenges in terms of recycling, pipeline blockage, and even secondary pollution in practical applications. Addressing these issues, the incorporation of MOFs into sponges proves to be an effective solution. Strategies like one-pot synthesis, in situ growth, and impregnation are commonly employed for loading MOFs onto sponges. This review comprehensively explores the synthesis strategies of MOFs and sponges, along with their applications in water treatment, aiming to contribute to the ongoing advancement of MOF materials.

Hybrid Materials: A Metareview

The field of hybrid materials has grown so wildly in the last 30 years that writing a comprehensive review has turned into an impossible mission. Yet, the need for a general view of the field remains, and it would be certainly useful to draw a scientific and technological map connecting the dots of the very different subfields of hybrid materials, a map which could relate the essential common characteristics of these fascinating materials while providing an overview of the very different combinations, synthetic approaches, and final applications formulated in this field, which has become a whole world. That is why we decided to write this metareview, that is, a review of reviews that could provide an eagle's eye view of a complex and varied landscape of materials which nevertheless share a common driving force: the power of hybridization.

Enhancing the optical properties of [P(MMA-co-AN)/ZrO2]TF by doping fluorescein dye, TD-DFT/DMOl3 simulations and COVID-19 main protease docking

Poly methyl methacrylate-co-acrylonitrile [P(MMA-co-AN)]HB hybrid blend was first synthesized by precipitation polymerization and characterized by static light scattering. With a thickness of 200 ± 5 nm, the hybrid nanocomposite of [P(MMA-co-AN)/ZrO2]HNC thin films were fabricated by spin coating method. X-Ray diffraction studies showed a monoclinic cell structure with an average crystalline size of 180 nm for the fabricated films. An improvement in the optical properties were figured out when fluorescein dye was doped in the hybrid nanocomposite. Where the optical energy gap was decreased from 4.31 to 4.025 eV for fluorescein doped hybrid nanocomposite. While a possible energy transfer between ZrO2 and fluorescein was investigated in the laser photoluminescence spectra. DFT-CASTEP simulations were deployed to calculate the theoretical optical properties for the molecules under consideration. The structural and optical simulations of [P(MMA-co-AN)/ZrO2]HNC were found to match the experimental data. Molecular docking studies of [P(MMA-co-AN)/ZrO2]Iso against the main protease of novel corona virus COVID 19 (PDB code 6LU7 Hormone) showed an interesting interaction.

"Photochemical Surgery" of 1D Metal-Organic Frameworks with a Site-Selective Solubilization/Crystallization Strategy

One-dimensional (1D) hybrid MOFs are attractive if they consist of different MOF blocks with interconnected channels. However, the precision synthesis of such 1D multiblock MOFs with the desired block lengths and sequences remains a formidable challenge. Herein we propose the "photochemical surgery" method, which combines top-down and bottom-up approaches to enable the site-selective solubilization (removal)/crystallization (reconstruction) of 1D MOFs. We employed photoreactive MOFs, which were prepared by complexing either Cd2+ or Zn2+ with a mixture containing a photochromic bispyridyl ligand (PyDTEopen or PyDTZEopen) and an isophthalate (5-nitroisophthalate (nip2-) or 5-bromoisophthalate (bip2-)). These MOFs were obtained as high-aspect-ratio, needlelike, colorless crystals that bore 1D channels oriented parallel to the long needle axis. When photoreactive DTECdMOFNO2 ([Cd(nip)(PyDTEopen)(H2O)]n), for example, was immobilized at both ends with a metal alloy on a glass substrate and exposed to UV light through a photomask for 60 min in N,N-dimethylformamide/methanol (DMF/MeOH), the unmasked part was removed via solubilization to produce a 50 μm gap. The resulting specimen was immersed for 24 h at 25 °C in DMF/MeOH containing the necessary components for the construction of DTZECdMOFNO2 ([Cd(nip)(PyDTZEopen)(H2O)]n). Eventually, the gap was filled with DTZECdMOFNO2 to produce a triblock hybrid MOF (DTECdMOFNO2-DTZECdMOFNO2-DTECdMOFNO2). The result of a guest diffusion experiment confirmed that the newly formed DTZECdMOFNO2 block shared its 1D channels with the host DTECdMOFNO2 blocks. "Photochemical surgery" can be applied to synthesize 1D hybrid MOFs bearing unconventional sequences and morphologies, e.g., honeycomb- and inverted-honeycomb-patterned hybrids.

Synthesis & fabrication of O-linked polymeric hybrids for recovery of textile dyes: Closed loop economy

Dyes are an important resource employed for the production systems in textile, paper, paint and leather industry. An estimate of 200,000 tons of dyes are discharged as textile effluent each year worldwide. It becomes imperative to recover these dyes by treating the effluents using economically viable routes. The present research was undertaken with the objective to attain zero emission and zero waste through development of novel polymeric hybrids as adsorbents. For this purpose, metal moieties (Al3+, Si4+, Ti4+ and Zr4+) were hybridized with polyacrylic acid, and cellulose acetate for the uptake of selected dyes under optimized parameters. The structural elucidation of four synthesized hybrids (MP-Al, MP-Si, MP-Ti and MP-Zr) by FTIR, EDX and TGA confirmed O-linked grafting of metal moieties with polymers and thermally stable porous materials. SEM micrographic images displayed void spaces providing channels for effective adsorption. The batch experiments demonstrated removal of malachite green (77-96%) and congo red (70-82%) upon contact of initial 45 min on polymeric hybrids On the other hand, pristine polyacrylic acid and cellulose acetate showed remarkably low removal of dyes. The adsorption mechanism is proposed as physical in nature following type II isotherm. Further, Langmuir and Ho's pseudo second order fitness was evaluated. In order to determine the economic viability of the present research, the real textile dyes were recovered in three consecutive cycles of adsorption and chemical treatment of hybrids. The results propose a system with positive impact on economy by maximum utilization of hybrids as adsorbents and recovery of textile dyes for reuse in textile processing.

High throughput computations of the effective removal of liquified gases by novel perchlorate hybrid material

The utilization of hybrid materials in separation technology, sorbents, direct air capture (DAC) technology, sensors, adsorbents, and chiral material recognition has increased in the past decade due to the recognized impact of atmospheric pollutants and hazardous industrial gases on climate change. A novel hybrid material, perchlorate hybrid (PClH), has been proposed in this study for the effective sensory detection and trapping of atmospheric pollutants and industrial hazardous gases. The study evaluated the structural properties, adsorption mechanism, electronic sensitivity, and topological analysis of PClH using highly accurate computational methods (M062X-D3BJ/def2-ccpVTZ and DSDPBEP86/def2-ccpVTZ). The computational analysis demonstrated that PClH has considerable adsorption energies and favorable interaction with CO2, NO2, SO2, COCl2, and H2S. PClH is more suitable for detecting liquefiable gases such as COCl2, CO2, and SO2, and can be easily recovered under ambient conditions. Developing such materials can contribute to reducing hazardous gases and pollutants in the atmosphere, leading to a cleaner and safer environment.

Periodic mesoporous organosilicas containing naphthalenediimides as organic sensitizers for sulfadiazine photodegradation

In this work, periodic mesoporous organosilicas (PMO) functionalized with the organic sentisizer naphthalenediimide (NDI) were employed as heterogeneous catalysts for the photodegradation of the antibiotic sulfadiazine (SDZ), taken as a model for contaminants of emerging concern (CECs). The catalysts, designated as PMONDI, were prepared by surfactant-directed co-condensation of the precursor N,N'-bis(3-triethoxysilylpropyl)- 1,4,5,8-naphthalenediimide with tetraethoxysilane. The synthesized PMONDI were characterized using transmission electron microscopy, nitrogen adsorption isotherms and small and large angle x-ray scattering. The performance of PMONDI catalysts in the photodegradation of SDZ was compared to that of TiO₂ nanoparticles impregnated into SBA-15 mesoporous silica (TiO₂/SBA-15), under irradiation with a Hg lamp with a bandpass filter of 320-500 nm. Under optimal conditions, PMONDI degraded 100% of the SDZ in 45 min, while the total degradation of SDZ was achieved only after 150 min with TiO₂/SBA-15. PMONDI also performed better than TiO₂/SBA-15 in reuse tests. The mechanism of photodegradation with PMONDI involves the formation of excited triplet states of NDI (³NDI*) upon irradiation, which can then react with molecular oxygen to form reactive oxygen species, which degrade SDZ. Analysis of the SDZ degradation products indicated two main pathways: (1) hydroxylation of the aniline ring and (2) SO₂ extrusion and rearrangement, followed by oxidation of the aniline ring to nitrobenzene. In conclusion, the great potential of the PMONDI materials as photocatalysts for CECs degradation was demonstrated in this work, encouraging further research on these materials for the degradation of pollutants.

Fe3O4/SiO2 decorated trimesic acid-melamine nanocomposite: a reusable supramolecular organocatalyst for efficient multicomponent synthesis of imidazole derivatives

This article describes supramolecular Fe3O4/SiO2 decorated trimesic acid-melamine (Fe3O4/SiO2-TMA-Me) nanocomposite that can be prepared with features that combine properties of different materials to fabricate a structurally unique hybrid material. In particular, we have focused on design, synthesis and evaluation a heterogeneous magnetic organocatalyst containing acidic functional-groups for the synthesis of biologically important imidazole derivatives in good to excellent yields. The introduced Fe3O4/SiO2-TMA-Me nanomaterial was characterized by different techniques such as FTIR, XRD, EDX, FESEM, TEM, TGA and DTA. As a noteworthy point, the magnetic catalytic system can be recycled and reused for more than seven consecutive runs while its high catalytic activity remains under the optimized conditions.

Ni-soc-MOF derived carbon hollow sphere encapsulated Ni3Se4 nanocrystals for high-rate supercapacitors

Carbon hollow sphere encapsulated Ni₃Se₄ (Ni₃Se₄@CHS) nanocrystals are prepared using the Ni-soc-MOF by pyrolysis and further selenization. Ni₃Se₄@CHS exhibits a capacitance of 1720 F g^-1 at 1 A g^-1 and a capacitance retention of 97% after 6000 cycles at 5 A g^-1. Moreover, the asymmetric supercapacitor of Ni₃Se₄@CHS//AC displays a wide potential window of 1.6 V, an energy density of 45.2 W h kg^-1 at a power density of 800 W kg^-1, and excellent cycling stability (89% capacitance retention) after 5000 cycles. Overall, this work establishes a significant step to synthesize a new carbon-based material with appreciable capacitance and long cycling durability for potential applications in energy storage and beyond.

Nanostructured silicate catalysts for environmentally benign Strecker-type reactions: status quo and quo vadis

Chemical processes are usually catalytic transformations. The use of catalytic reagents can reduce the reaction temperature, decrease reagent-based waste, and enhance the selectivity of a reaction potentially avoiding unwanted side reactions leading to green technology. Chemical processes are also frequently based on multicomponent reactions (MCRs) that possess evident improvements over multistep processes. Both MCRs and catalysis tools are the most valuable principles of green chemistry. Among diverse MCRs, the three-component Strecker reaction (S-3-CR) is a particular transformation conducive to the formation of valuable bifunctional building blocks (α-amino nitriles) in organic synthesis, medicinal chemistry, drug research, and organic materials science. To be a practical synthetic tool, the S-3-CR must be achieved using alternative energy input systems, safe reaction media, and effective catalysts. These latter reagents are now deeply associated with nanoscience and nanocatalysis. Continuously developed, nanostructured silicate catalysts symbolize green pathways in our quest to attain sustainability. Studying and developing nanocatalyzed S-3-CR condensations as an important model will be suitable for achieving the current green mission. This critical review aims to highlight the advances in the development of nanostructured catalysts for technologically important Strecker-type reactions and to analyze this progress from the viewpoint of green and sustainable chemistry.

Concave octopus-like PtCu nanoframe mediated photo-electro Fenton catalysis for fast organic dyestuff elimination

In this work, a photo-electro Fenton catalytic nanoplatform based on concave octopus-like PtCu nanoframes was fabricated for organic dyestuff degradation. The electrochemical oxidation reaction was performed to generate hydrogen peroxide (H2O2) on the interface of PtCu nanoframes via a promising electro-Fenton process for on-demand aqueous remediation.