Mesoporous Morphology Research Articles

Transition metal modified Al2O3 mesoporous nanospheres for catalysis of organic reactions

The performance of metal oxide-based catalysts are usually determined by their characteristics such as material composition, morphology, and surface/interface properties. Therefore, rational design of metal oxide-based catalysts with special surface/interface characteristics and porous microstructure still needs further research. In this work, a facile two-step solvothermal-annealing method is developed for the synthesis of transition metal (TM) modified Al2O3 (TM-Al2O3, TM = Cu, Fe, Ni, Co) nanospheres. The influences of different ratios of solvents (e.g., water and glycerol) on the morphology and particle size of the nanocatalysts are explored. Benefitting from the nano-spherical morphology and unique mesoporous structure, the representative catalyst (i.e., Cu-Al2O3) exhibits favorable catalytic performance in 4-nitrophenol reduction and benzyl alcohol oxidization reactions. The turnover frequency of Cu-Al2O3 is high up to 35.9 min−1 for the reduction of 4-nitrophenol, which is higher than that of its counterparts (i.e., Fe-Al2O3, Ni-Al2O3, and Ni-Al2O3) and many recently reported Al2O3-based catalysts. Moreover, the pH of the reaction system is regulated to enhance the catalytic efficiency in selective oxidization of benzyl alcohol by an additive addition strategy. These results suggest that the nano-spherical and mesoporous morphology is indeed effective for the activity enhancement of TM-Al2O3 catalysts. The same catalyst designing concept and performance regulation strategy may be extended to other TM-modified metal oxide systems, making it possible to tune the catalytic behavior for various chemical reactions.

Abalone shell-derived Mg-doped mesoporous hydroxyapatite microsphere drug delivery system loaded with icariin for inducing apoptosis of osteosarcoma cells.

Hydroxyapatite (HAP) porous microspheres with very high specific surface area and drug loading capacity, as well as excellent biocompatibility, have been widely used in tumour therapy. Mg2+ is considered to be a key factor in bone regeneration, acting as an active agent to stimulate bone and cartilage formation, and is effective in accelerating cell migration and promoting angiogenesis, which is essential for bone tissue repair, anti-cancer, and anti-infection. In this study, abalone shells from a variety of sources were used as raw materials, and Mg2+-doped abalone shell-derived mesoporous HAP microspheres (Mg-HAP) were prepared by hydrothermal synthesis as Mg2+/ icariin smart dual delivery system (ICA-Mg-HAP, IMHA). With increasing of Mg2+ doping, the surface morphology of HAP microspheres varied from collapsed macroporous to mesoporous to smooth and non-porous, which may be due to Mg2+ substitution or coordination in the HAP lattice. At 30% Mg2+ doping, the Mg-HAP microspheres showed a more homogeneous mesoporous morphology with a high specific surface area (186.06 m2/g). The IMHA microspheres showed high drug loading (7.69%) and encapsulation rate (83.29%), sustained Mg2+ release for more than 27 days, sustained and stable release of icariin for 60 hours, and good responsiveness to pH (pH 6.4 > pH 5.6). In addition, the IMHA delivery system stimulated the rapid proliferation of bone marrow mesenchymal stem cells and induced apoptosis in MG63 cells by blocking the G2 phase cycle of osteosarcoma cells and stimulating the high expression of apoptotic genes (Bcl-2, caspase-3, -8, -9). This suggests that the abalone shell-based IMHA may have potential applications in drug delivery and tumour therapy.

Application of green synthesized biogenic Nd2Zr2O7 supported on dendritic fibrous nano-titanium for photocatalytic and antibacterial activities

The combination of a phase junction and fibrous structure has been proven to improve the catalytic ability and performance, as well as the separation of nano titanium oxide. However, there is still a pressing need for facile and environmentally sustainable fabrication techniques. In this research, we introduce an innovative approachfor the fabrication of dandelion-like TiO2 with anatase/TiO2 phase interfaces and an extremely specific exterior layer using a user-friendly and green deep eutectic solvent-tuning method. We have successfully synthesized DaNd2Zr2O7 nanospheres on dendritic fibrous nanotitanium (DFNT@DaNd2Zr2O7) using a straightforward method. The DFNT@DaNd2Zr2O7 composite retained its mesoporous structure and crystalline morphology, despite the loading of DaNd2Zr2O7. These nanocomposites are employed as active photocatalysts under UV radiation and can effectively treat water contaminated with organic pollutants and microorganisms. Additionally, they exhibit antimicrobial properties against gram-positive species like pathogenic strains of Enterococcus faecalis and Staphylococcus aureus, as well as Gram-negative species like Escherichia coli, Furthermore and Klebsiella pneumonia, these nanocomposites exhibit excellent stability over ten cycles, reinforcing their potential as proficient catalysts to address environmental concerns.

Improved structure of Zr-BTC metal organic framework using NH2 to enhance CO2 adsorption performance

Modified mesoporous NH2-Zr-BTC mixed ligand MOF nanocomposites were synthesized via the hydrothermal method as a novel adsorbent for CO2 capture. The newly modified MOF-808 with NH2 demonstrated a similar mesoporous morphology as MOF-808, whereas the specific surface area, pore volume, and average particle size, respectively, increased by 15%, 6%, and 46% compared to those of MOF-808. The characterization analyses exhibited the formation of more active groups on the adsorbent surface after modification. In addition, a laboratory adsorption setup was used to evaluate the effect of temperature, pressure, and NH2 content on the CO2 adsorption capacity in the range of 25–65 °C, 1–9 bar, and 0–20 wt%, respectively. An increase in pressure and a decrease in temperature enhanced the adsorption capacity. The highest equilibrium adsorption capacity of 369.11 mg/g was achieved at 25 °C, 9 bar, and 20 wt% NH2. By adding 20 wt% NH2, the maximum adsorption capacity calculated by the Langmuir model increased by about 4% compared to that of pure MOF-808. Moreover, Ritchie second-order and Sips models were the best-fitted models to predict the kinetics and isotherm data of CO2 adsorption capacity with the high correlation coefficient (R2 > 0.99) and AARE% of less than 0.1. The ΔH°, ΔS°, and ΔG° values were − 17.360 kJ/mol, − 0.028 kJ/mol K, and − 8.975 kJ/mol, respectively, demonstrating a spontaneous, exothermic, and physical adsorption process. Furthermore, the capacity of MH-20% sample decreased from 279.05 to 257.56 mg/g after 15 cycles, verifying excellent stability of the prepared mix-ligand MOF sorbent.

Influence of sulphonation on Al-MCM-41 catalyst for effective bio-glycerol conversion to Solketal

Al-MCM-41 and sulphate modified Al-MCM-41 catalysts with variable sulphate loadings (0.25-1SAM) were synthesized through sol-gel and impregnation techniques respectively for the transformation of glycerol into solketal, a fuel additive via acetalization reaction. The mesoporous structure, surface morphologies, composition and porosity of the prepared catalysts were subjected to characterization by Low angle XRD, SEM-EDAX, TEM, FT-IR, XPS and BET-surface area studies. The strength and quantification of acid sites were obtained from TPD of NH3. Pyridine-adsorbed FTIR and 27Al MAS NMR data distinguished Lewis and Brønsted acid sites present on the catalysts. Among the synthesized catalysts, 1 N sulphated Al-MCM-41 was a better catalyst that promotes a higher solketal formation rate of 23.5 mmol h−1g cat−1 by the acetalization of glycerol. This is much higher in comparison to 4 times lesser activity of 6.1 mmol h−1gcat−1 exhibited by the parent Al-MCM-41. This catalyst further showed consistent activity and reusability up to 5 cycles. Large surface area, total acidity, strong Lewis acid sites, compatible surface characteristics of 1 N sulphated Al-MCM-41 endorse the higher acetalization activity of the catalyst. As a result, these parameters have been regarded as crucial considerations in designing a better catalyst in the effective conversion of glycerol to solketal.

Adsorptive separation of CH4, H2, CO2, and N2 using fullerene pillared graphene nanocomposites: Insights from molecular simulations.

The adsorptive separation performances of fullerene pillared graphene nanocomposites (FPGNs) with tunable micro and meso porous morphology are investigated for the binary mixtures of CH4, H2, CO2 and N2 by using grand canonical Monte Carlo (GCMC) simulations. Different fullerene types are considered in designs as pillar to investigate the effects of porosity on the gas separation performances of FPGNs, and the GCMC simulations are performed for an equimolar binary mixture of CO2/H2, CO2/CH4, CO2/N2 and CH4/H2 inspired by industrial gas mixtures. It is found that CO2/N2, CO2/H2 and CH4/H2 selectivity of FPGNs are about 72, 410 and 145 at 298K and 1bar, which are higher than those for several adsorbent materials reported. Five different FPGN models which contain covalently bonded periodical fullerene and graphene units were constructed using C60, C180, C320, C540 and C720 fullerenes, followed by geometry optimization using Open Babel. All GCMC simulations of adsorption were performed in the RASPA. The adsorption isotherms of FPGNs for pure gases are comparatively examined, and their performances are discussed based on the pore structure and isosteric heat of adsorption. Then, the separation factors of FPGNs for equimolar binary mixtures of these gases are elucidated from the difference in the heat of adsorption and the adsorption selectivity.

Efficient and selective cycloaddition of carbon dioxide, amines, and alkenes using Gd2ZnMnO6/Zn2MnO4 supported on dendritic fibrous nano-titanium

The co-fabrication of a phase junction and fibrous structure has been demonstrated to enhance the catalytic ability, catalytic performance, and separation of nano titanium oxide. Nevertheless, despite these benefits, there remains a critical need for facile and environmentally sustainable fabrication methods. In this study, we present an innovative approach to synthesizing dandelion-like TiO2 with anatase/TiO2 phase interfaces and a highly specific exterior level using a user-friendly and green deep eutectic solvent-tuning method. This impressive outer layer is the result of the 3D-ranked assembly of 2D ultrathin nanosheets with mesopores. Additionally, we have successfully fabricated Gd2ZnMnO6/Zn2MnO4 nanospheres on dendritic fibrous nanotitanium (DFNT@Gd2ZnMnO6/Zn2MnO4) via a facile synthetic pathway. Notably, the overall mapping of the DFNT@Gd2ZnMnO6/Zn2MnO4 composite remained largely unchanged after the loading of Gd2ZnMnO6/Zn2MnO4, and its mesoporous architecture and crystalline morphology were preserved. The investigation of diverse DFNT@Gd2ZnMnO6/Zn2MnO4 configurations as a nanocatalysts for the preparation of 3-aryl-2-oxazolidinones by anilines, carbon dioxide, and olefins was also conducted. It demonstrated appropriate stability over ten cycles, indicating its potential as a highly proficient catalyst to mitigate environmental concerns.

Exceptional arsenic removal using novel mesoporous Mg-Al-Ti ternary composite oxide nanoparticles prepared via self-assembly templating method

Arsenic contamination of water through natural and anthropogenic activities is a grave problem today. One of the most efficient ways to remove arsenic from water is through adsorption. Porous nanomaterials show high adsorption capacities due to high surface area, and efficient mass transfer with plenty of active adsorption sites. Porous metal oxides have been successfully employed to remove arsenic from water previously. However, ternary metal oxide composites hold potential for novel adsorbent materials but have yet to be explored in depth. Mesoporous Mg-Al-Ti oxide composite oxide nanoparticles with varying compositions were synthesized via a low-cost, scalable, evaporation-induced self-assembly technique using P123 block copolymer as a soft template. All the compositions of synthesized ternary oxide nanoparticles exhibited exceptionally high arsenic adsorption capacities ranging from 543 to 1215 mg/g for As(V) and 359.6–919.4 mg/g for As(III) along with 96–98% removal of arsenic from real groundwater samples of up to 489.3 ppb. The composites show mesopores and high surface area ranging from 93-393.6 m2/g with very small particle size ranging from 8 to 12 nm. The nanoparticles have shown great selectivity towards arsenic and exceptional adsorption performance in a wide pH range. High volume-to-surface area ratio, an abundance of hydroxyl groups, interconnected mesoporous morphology, and high point of zero charge pH contribute to the high adsorption capacity of the composite oxides. Mesoporous Mg-Al-Ti ternary oxide composite nanoparticles have shown higher adsorption capacity towards arsenic than many existing adsorbent material materials and can be a very promising candidate for arsenic remediation from water.

Novel Mesoporous and Multilayered Yb/N-Co-Doped CeO2 with Enhanced Oxygen Storage Capacity.

A cubic fluorite-type CeO2 with mesoporous multilayered morphology was synthesized by the solvothermal method followed by calcination in air, and its oxygen storage capacity (OSC) was quantified by the amount of O2 consumption per gram of CeO2 based on hydrogen temperature programmed reduction (H2-TPR) measurements. Doping CeO2 with ytterbium (Yb) and nitrogen (N) ions proved to be an effective route to improving its OSC in this work. The OSC of undoped CeO2 was 0.115 mmol O2/g and reached as high as 0.222 mmol O2/g upon the addition of 5 mol.% Yb(NO3)3∙5H2O, further enhanced to 0.274 mmol O2/g with the introduction of 20 mol.% triethanolamine. Both the introductions of Yb cations and N anions into the CeO2 lattice were conducive to the formation of more non-stoichiometric oxygen vacancy (VO) defects and reducible-reoxidizable Cen+ ions. To determine the structure performance relationships, the partial least squares method was employed to construct two linear functions for the doping level vs. lattice parameter and [VO] vs. OSC/SBET.

Solution-based self-assembly synthesis of two-dimensional-ordered mesoporous conducting polymer nanosheets with versatile properties.

Conducting polymers with conjugated backbones have been widely used in electrochemical energy storage, catalysts, gas sensors and biomedical devices. In particular, two-dimensional (2D) mesoporous conducting polymers combine the advantages of mesoporous structure and 2D nanosheet morphology with the inherent properties of conducting polymers, thus exhibiting improved electrochemical performance. Despite the use of bottom-up self-assembly approaches for the fabrication of a variety of mesoporous materials over the past decades, the synchronous control of the dimensionalities and mesoporous architectures for conducting polymer nanomaterials remains a challenge. Here, we detail a simple, general and robust route for the preparation of a series of 2D mesoporous conducting polymer nanosheets with adjustable pore size (5-20 nm) and thickness (13-45 nm) and controllable morphology and composition via solution-based self-assembly. The synthesis conditions and preparation procedures are detailed to ensure the reproducibility of the experiments. We describe the fabrication of over ten high-quality 2D-ordered mesoporous conducting polymers and sandwich-structured hybrids, with tunable thickness, porosity and large specific surface area, which can serve as potential candidates for high-performance electrode materials used in supercapacitors and alkali metal ion batteries, and so on. The preparation time of the 2D-ordered mesoporous conducting polymer is usually no more than 12 h. The subsequent supercapacitor testing takes ~24 h and the Na ion battery testing takes ~72 h. The procedure is suitable for users with expertise in physics, chemistry, materials and other related disciplines.

Quantum dot-derived carbon nanopocket-confined Co3O4 within mesoporous carbon nanofiber for Cu-free anode of flexible Li-ion batteries

Cu-free flexible anodes, which are promising alternatives to the conventional anode type, have received global attention owing to their advantages, such as flexible deformability and elimination of interfacial trouble between active materials and current collector. However, these Cu-free anodes suffer from low specific capacitance and poor mechanical properties. To overcome these issues, we introduced carbon quantum dots (CQDs) as inner structure modification agents and Co3O4 nanoparticles within a mesoporous carbon nanofibers (CNF). Herein, we report a novel strategy for developing highly flexible Cu-free anode using the mesoporous CNF structure together with quantum dot-induced carbon nanopocket effect. During the carbonization process, the surface functional groups of the CQDs decomposed, which led to the formation of a carbon nanopocket. This carbon nanopocket effectively suppressed the particle growth of cobalt oxide. Moreover, mesoporous surface morphology was successfully developed using a post-oxidation process. The resultant Co3O4/CQD-PCNF flexible anode showed superior anode performances, including the high specific capacity of 783.43 and 227.59 mAh/g at a current density of 100 and 2,000 mA/g, respectively, with an excellent high-rate capability of 79.6% after 1,000 cycles of intense flexible test. Therefore, the Co3O4/CQD-PCNF Cu-free anode can provide a new direction to electrode modification strategies for achieving free-standing anode for highly flexible Li-ion batteries.

Compact-porous hole-transport-layer for highly efficient near-infrared region transparent perovskite solar cells for tandem applications

Wide-bandgap perovskites solar cells (PSCs) are vital as top cells in perovskite-based tandem solar cells (TSCs). However, poor band alignment with the charge transport layer and unwanted parasitic absorption in the top semitransparent-PSC (ST-PSC) are major factors limiting the power conversion efficiency (PCE) of TSCs. Herein, we present a compact-porous nickel oxide (cp-NiOx) hole-transport layer (HTL) sequentially fabricated using a sol-gel suspension and colloidal suspension of highly crystalline NiOx. The cp-NiOx film exhibited enhanced transparency, mesoporous surface morphology, and better energy band alignment with a 1.68 eV perovskite film for fabricating highly near-infrared transparent (∼92 % (@800–1200 nm)) ST-PSCs. The best cell achieved a PCE of 15.9 %. In addition, a four-terminal perovskite/silicon TSC based on the cp-NiOx HTL achieved an outstanding PCE of ∼26.0 %. The tailored energy band structure and reduced parasitic absorption in the near-infrared region of the ST-PSCs based on the cp-NiOx HTL enabled fabrication of highly efficient inverted ST-PSCs for perovskite/silicon TSCs.

Spray‐Deposited, Virus‐Templated SnO2 Mesoporous Electron Transport Layer for High‐Efficiency, Sequential‐Deposited Perovskite Solar Cells

In recent years, researchers have developed spray deposition technology to fabricate tin oxide electron transport layer (ETL) with the aim of manufacturing high‐efficiency, large‐area perovskite solar cell (PSC). However, the power conversion efficiency (PCE) of PSC based on sprayed SnO2 ETL remains inferior to that of the spin‐coated SnO2 ETL. Herein, the combined use of spray deposition and genetically engineered M13 bacteriophages for the deposition of M13‐SnO2 biohybrid ETL over large‐area (62.5 cm2) substrates is demonstrated. The spray‐deposited M13‐SnO2 ETLs exhibit mesoporous morphologies with >85% transmittance in UV–vis region. Through the use of M13‐SnO2 ETL, the sequential‐deposited PSCs achieve a maximum PCE of ≈22.1%. The improved performance of the PSC is attributable to the mesoporous morphology of M13‐SnO2 ETL that facilitates the growth of larger perovskite grains. The PSCs based on M13‐SnO2 ETLs also display highly consistent photovoltaic performance which manifests the excellent scalability of the spraying process. Furthermore, M13‐SnO2‐based PSCs exhibit higher ambient stability compared to the SnO2‐based PSCs, showing that the use of M13 bacteriophage is incredibly beneficial to both the efficiency and stability of PSCs.

Multifunctional dual Z-scheme heterostructured Sm2O3-WO3-La2O3 nanocomposite: Enhanced electrochemical, photocatalytic, and antibacterial properties

In this study, heterostructured dual Z-scheme Sm2O3-WO3-La2O3 nanocomposite (NC) and bare Sm2O3, WO3, and La2O3 nanostructured (NSs) were prepared using a co-precipitation approach. The comparative electrochemical, photocatalytic, and antimicrobial properties of NC and NSs were studied. The XRD spectrum exhibits the formation of bare NSs and NC having cubic-Sm2O3, monoclinic-WO3, and hexagonal-La2O3 phases. FESEM results showed mesoporous morphology of NC. The higher electrical conductivity 261.33 mho-cm−1 and lower optical energy bandgap 2.55 eV were obtained for NC. The photodegradation tests exhibited that NC photocatalyst has degraded 99% (methylene blue), 96% (Methyl orange), 99% (safranin-O), 48% (p-nitroaniline), and 98% (methyl red) dyes pollutants in 40 min sunlight radiation and showed strong inhibition activity against E. coli, K. pneumoniae, S. aureus, P. Vulgaris, and P. aeruginosa bacterial strains with zones of inhibition (ZOI) 31 mm, 30 mm, 30 mm, 28 mm, and 31 mm, respectively. Electrochemical studies revealed the excellent capacitive characteristics of NC with a specific capacitance 532F/g at a scan rate 5 mV/s, energy density 48.0278 W h Kg−1, and power density 0.3782 KW Kg−1 at 0.006 A/cm2 current density. Furthermore, the present study revealed a novel composition for environmental remediation and energy storage applications.

Extraction and purification of Lawsonia inermis (laali) dyes for applications in dye-sensitized solar cell

This study explores the extraction of dyes from Lawsonia inermis (Laali) and the effects of purification on the dyes for solar cell applications. The TiO2 thin films were synthesized through Doctor Blade’s technique while the dye was applied on the thin film using a simple drop-casting method. Characterization of the doctor-blade deposited TiO2 thin-film using XRD confirmed the successful deposition of anatase crystallite structure with a mesoporous morphology confirmed using SEM analysis. The UV-Vis, FTIR, and EIS characterizations of the dyes showed increase in band gap, adequate functional groups and lower charge resistance respectively after the purification, which could contribute positively to enhancing the efficiency of solar cell devices.

Nanoscale morphology tailoring in plasma deposited CN x layers

Magnetron discharge plasma was applied for the synthesis of CN x thin layers using methane and nitrogen gas precursors. The incorporation of nitrogen in the carbon network resulted in the dramatic evolution of growth morphology: from a ‘buried’ porous layer observed at low nitrogen incorporation to aligned bundles of nanorods grown perpendicular to the substrate surface at maximum discharge power and nitrogen flow. The films deposited at the low discharge power and high nitrogen incorporation exhibited a mesoporous sponge-like morphology after vacuum annealing. Relevant physical mechanisms responsible for the formation of nano- and mesoshaped morphology are discussed in terms of the effects of internal mechanical stresses and plasma etching. In addition, the sensing properties of the sponge-like layer were preliminarily examined in water vapor and ammonia ambients. The CN x films showed enhanced sensitivity to ammonia and reverse electrical response to moisture in comparison with a nitrogen-free nanoporous carbon film, which were assigned to modification of the electronic properties of the nitridated surface.

A cost-effective H2S pollutant electro-transformation to hydrogen clean fuel and value-added semiconducting materials: A green alternative to Claus process

A straightforward strategy to resolve the H2S problem is its neutralization in alkaline media, followed by electrolysis of the obtained solution upon suitable electrodes. Herein, we report for the first time that via galvanostatic electrolysis of the resulting alkaline sulfide medium over copper electrodes, this harmful pollutant could be safely as well as cost-effectively transformed to hydrogen clean fuel and a value-added eco-friendly semiconducting material. The strong interaction of copper with bisulfide (the dominant species of the medium at pH 11) resulted in a significant decrease in the system impedance, accompanied by less electricity consumption during the process. A nano/micro-structured, mesoporous morphology was observed for the anodic product (surface area: 11.4 m2/g). Photoelectrochemical and diffuse reflectance as well as XRD, EDX, XPS and photoluminescence investigations revealed that the material synthesized upon the anode surface was a narrow bandgap (Eg=1.63eV) p-type semiconductor. In addition to the economic perspective of the proposed electrolysis process (3 ∼ 6 USD/kgH2), the underlying mechanism of simultaneous production of semiconductor (CuS) and H2 was thoroughly discussed.

Atomically Dispersed Manganese on Carbon Substrate for Aqueous and Aprotic CO2 Electrochemical Reduction.

CO2 utilization and conversion are of great importance in alleviating the rising CO2 concentration in the atmosphere. Here, a single-atom catalyst (SAC) is reported for electrochemical CO2 utilization in both aqueous and aprotic electrolytes. Specifically, atomically dispersed Mn-N4 sites are embedded in bowl-like mesoporous carbon particles with the functionalization of epoxy groups in the second coordination spheres. Theoretical calculations suggest that the epoxy groups near the Mn-N4 site adjust the electronic structure of the catalyst with reduced reaction energy barriers for the electrocatalytic reduction of CO2 to CO. The resultant Mn-single-atom carbon with N and O doped catalyst (MCs-(N,O)) exhibits extraordinary electrocatalytic performance with a high CO faradaic efficiency of 94.5%, a high CO current density of 13.7 mAcm-2 , and a low overpotential of 0.44 V in the aqueous environment. Meanwhile, as a cathode catalyst for aprotic Li-CO2 batteries, the MCs-(N,O) with well-regulated active sites and unique mesoporous bowl-like morphology optimizes the nucleation behavior of discharge products. MCs-(N,O)-based batteries deliver a low overpotential and excellent cyclic stability of 1000h. Thefindings in this work provide a new avenue to design and fabricate SACs for various electrochemical CO2 utilization systems.

Effects of Various Ripening Media on the Mesoporous Structure and Morphology of Hydroxyapatite Powders.

Mesoporous hydroxyapatite (HA) materials demonstrate advantages as catalysts and as support systems for catalysis, as adsorbent materials for removing contamination from soil and water, and as nanocarriers of functional agents for bone-related therapies. The present research demonstrates the possibility of the enlargement of the Brunauer-Emmett-Teller specific surface area (SSA), pore volume, and average pore diameter via changing the synthesis medium and ripening the material in the mother solution after the precipitation processes have been completed. HA powders were investigated via chemical analysis, X-ray diffraction analysis, Fourier-transform IR spectroscopy, transmission electron microscopy (TEM), and scanning (SEM) electron microscopy. Their SSA, pore volume, and pore-size distributions were determined via low-temperature nitrogen adsorption measurements, the zeta potential was established, and electron paramagnetic resonance (EPR) spectroscopy was performed. When the materials were synthesized in water-ethanol and water-acetone media, the SSA and total pore volume were 52.1 m2g-1 and 116.4 m2g-1, and 0.231 and 0.286 cm3g-1, respectively. After ripening for 21 days, the particle morphology changed, the length/width aspect ratio decreased, and looser and smaller powder agglomerates were obtained. These changes in their characteristics led to an increase in SSA for the water and water-ethanol samples, while pore volume demonstrated a multiplied increase for all samples, reaching 0.593 cm3g-1 for the water-acetone sample.

Electrochemical Synthesis, Magnetic and Optical Characterisation of FePd Dense and Mesoporous Nanowires.

Dense and mesoporous FePd nanowires (NWs) with 45 to 60 at.% Pd content were successfully fabricated by template- and micelle-assisted pulsed potentiostatic electrodeposition using nanoporous anodic alumina and polycarbonate templates of varying pore sizes. An FePd electrolyte was utilized for obtaining dense NWs while a block copolymer, P-123, was added to this electrolyte as the micelle-forming surfactant to produce mesoporous NWs. The structural and magnetic properties of the NWs were investigated by electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The as-prepared NWs were single phase with a face-centered cubic structure exhibiting 3.1 µm to 7.1 µm of length. Mesoporous NWs revealed a core-shell structure where the porosity was only witnessed in the internal volume of the NW while the outer surface remained non-porous. Magnetic measurements revealed that the samples displayed a soft ferromagnetic behavior that depended on the shape anisotropy and the interwire dipolar interactions. The mesoporous core and dense shell structure of the NWs were seen to be slightly affecting the magnetic properties. Moreover, mesoporous NWs performed excellently as SERS substrates for the detection of 4,4'-bipyridine, showing a low detection limit of 10-12 M. The signal enhancement can be attributed to the mesoporous morphology as well as the close proximity of the embedded NWs being conducive to localized surface plasmon resonance.