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Titanium phosphate is currently a promising material for proton exchange membrane fuel cells applications (PEMFC) allowing for operation at high temperature conditions. In this work, titanium phosphate was synthesized from tetra iso-propoxide (TTIP) and orthophosphoric acid (H₃PO₄) in different ratios by a sol gel method. High BET surface areas of 271 m².g^-1 were obtained for equimolar Ti:P samples whilst reduced surface areas were observed by varying the molar ratio either way. Highest proton conductivity of 5.4×10^-2S.cm^-1 was measured at 20°C and 93% relative humidity (RH). However, no correlation was observed between surface area and proton conductivity. High proton conductivity was directly attributed to hydrogen bonding in P-OH groups and the water molecules retained in the sample structure. The proton conductivity increased with relative humidity, indicating that the Grotthuss mechanism governed proton transport. Further, sample Ti/P with 1:9 molar ratio showed proton conductivity in the order of 10^-1 S.cm^-1 (5% RH) and ~1.6×10^-2S.cm^-1 (anhydrous condition) at 200°C. These proton conductivities were mainly attributed to excess acid locked into the functionalized TiP structure, thus forming ionisable protons.

The latest addition to the nanocarbon family, graphene, has been proclaimed to be the material of the century. Its peculiar band structure, extraordinary thermal and electronic conductance and room temperature quantum Hall effect have all been used for various applications in diverse fields ranging from catalysis to electronics. The difficulty to synthesize graphene in bulk quantities was a limiting factor of it being utilized in several fields. Advent of chemical processes and self-assembly approaches for the synthesis of graphene analogues have opened-up new avenues for graphene based materials. The high surface area and rich abundance of functional groups present make chemically synthesized graphene (generally known as graphene oxide (GO) and reduced graphene oxide (RGO) or chemically converted graphene) an attracting candidate in biotechnology and environmental remediation. By functionalizing graphene with specific molecules, the properties of graphene can be tuned to suite applications such as sensing, drug delivery or cellular imaging. Graphene with its high surface area can act as a good adsorbent for pollutant removal. Graphene either alone or in combination with other materials can be used for the degradation or removal of a large variety of contaminants through several methods. In this review some of the relevant efforts undertaken to utilize graphene in biology, sensing and water purification are described. Most recent efforts have been given precedence over older works, although certain specific important examples of the past are also mentioned.

The structural and elastic properties of neutral and ionized dichlorocarbene (CCl₂) functionalized single-walled carbon nanotubes (SWCNTs) were studied using density functional theory (DFT). The Young’s modulus of ionized pristine SWCNTs is found to decrease in comparison to that of neutral models. The interesting effect of increase in Young’s modulus values of ionized functionalized SWCNTs is observed. We ascribe this feature to the concurrent processes of the bond elongation on ionization and the local deformation on cycloaddition. The strong dependence of the elasticity modulus on the number of addends is also observed. However, the CCl₂-attached SWCNTs in their neutral and ionized forms remain strong enough to be suitable for the reinforcement of composites. In contrast to the elastic properties, the binding energies do not change significantly, irrespective of CCl₂ coverage.

Combining hybrid nanostructures of metal nanoparticles (NPs) and carbon nanotubes could afford a novel strategy to prepare promising nanomaterials for the highly sensitive sensors and imaging science applications. Conventional acid oxidation process was used to obtain carboxylic acid bound multi-walled carbon nanotubes (MWNTs) which was further acylated with thionyl chloride to give acyl chloride functionalized MWNTs. Thiol functionalized MWNTs were synthesized by amidation reaction of the acylated MWNTs with cysteamine. Further, gold nanoparticles (GNPs) were successfully fabricated on the tube walls to yield the CNT/Au hybrid. Fourier transform infrared spectroscopy and energy dispersive X-ray studies were used to characterize the surface chemical functionalities and composition of MWNTs, respectively. Evidence for the attachment of GNPs to thiol functionalized MWNTs was obtained from ultraviolet–visible absorption spectra. In addition, TEM images provided a vivid image of uniform decoration of GNPs on the nanotube sidewalls.

Carbon nanotubes (CNTs) were stabilized in solution through sonication-induced polymerization of acrylated epoxidized soybean oil (AESO) monomer. Transmission electron microscopy and atomic force microscopy showed that the resulting polymer coatings of nanotubes in solution were approximately 10–30 nm in thickness. Raman spectroscopy suggests that AESO intercalates Nanocyl bundles and coats the exterior of HiPco bundles. Using sonication a stable dispersion of as-produced carbon nanotube powder was formed. Mechanical measurements on macroscale composites samples showed modulus enhancement consistent with a lower bound rule of mixtures.

Trifluoropropyl-trichlorosilane reagents were used to tailor the surface chemistry of porous nano-structured thin films fabricated using glancing angle deposition (GLAD). GLAD produces high surface area films of isolated columnar structures and provides complete control over the film morphology. Here, the chemical tunability of these GLAD films was investigated using solution and vapor-phase surface functionalization methods. All films were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy and advancing aqueous contact angle measurements. Our results indicate that the surface chemistry of the GLAD films was effectively changed after functionalization by either approaches. We also note that vapor-phase functionalization provides more consistent results and eliminates the need for organic solvents, making it an ideal method for tailoring the surface properties of GLAD films for specific applications.

A new technique based on an electrostatic-force-directed-self-assembly was developed to fabricate thin films of multi-walled carbon nanotubes (MWCNTs) on thin dielectric wires. This technique was further developed to achieve functionalization of the nanotubes via acid-free dry route in a few seconds. The functionalization was confirmed by Fourier transform infrared and Raman spectroscopic measurements. The electrostatically self-assembled films provided significantly enhanced sensitivity for detection of alcohol vapors. Sensors were tested for response of alcohol concentrations as low as 200 ppm (parts per million) with a sensitivity of 4% and high repeatability. Recovery of sensors was observed to be within 200 s. Selectivity of the sensors for different organic vapors was defined based on the recovery time. Operation of sensors did not require high temperatures. It was realized that corona-based electrostatic self-assembly (CESA) pattering technique for batch fabrication of the sensors was fast, simple, low-cost, and required no specialized equipment.

In this report, the functionalization of MWCNTs in sulfuric/nitric acid is studied, and the influences of acid concentration, temperature and time on functionalization are assessed. Fourier Transmission Infrared (FTIR) spectroscopy was employed to study the functional groups of different samples. The optimal results for complete functionalization were achieved by the addition of 5 mg/ml of MWCNTs to acid, at a temperature of 100°C with 3 h of soaking time. The correlation between the FTIR and Raman spectra of the optimized sample was determined, and the effect of functional groups on the G and D bands is discussed.

Carbon nanotubes (CNTs) have been successfully synthesized by using in-house fabricated Double Stage Chemical Vapor Deposition (DS-CVD) technique, using acetylene (C₂H₂) and hydrogen (H₂) as the precursor gases. The purity, morphology and the structure of CNTs were then characterized using Field Emission Scanning Microscope (FESEM), Transmission Electron Microscope (TEM) and Thermogravimetric Analysis (TGA). The effects of the process parameters were examined whereby the experimental design of the investigation was conducted using Design Expert^® Version 6.0.8. The statistical analysis reveals that the optimized conditions for the best CNTs yield production at 850°C reaction temperature, 60 min reaction time, with gas flow rates at 40 and 150 ml/min for C₂H₂ and H₂, respectively. The CNTs produced were successfully used as column chromatographic media. Due to its nanosized structured dimension, CNTs' have tremendously large surface area and that lead to highly efficient protein purification. Skim latex protein has been used as the model protein and we aim to recover useful proteins and enzymes from this known wasteful material. During the purification, the process parameters such as pH and ionic strength of the running buffer were optimized to enhance protein purification. Results reveal that CNTs behave efficiently as a hydrophobic interaction chromatographic media.

Nature of the interaction potential of different adsorbates on different zigzag single-walled carbon nanotubes is investigated. The intermolecular potentials for H₂ absorbed in carbon nanotubes (5, 0), (6, 0), (7, 0), (8, 0), (9, 0), and (10, 0) are computed and sketched. This study is extended to N₂ adsorbed on (4, 0) and BH₃ adsorbed on (10, 0) tubes. The equilibrium positions of the adsorbates obtained from the potential model serve as an initial guess in designing the CNT + adsorbate complex in the simulation cell and this process considerably reduces the computation time. Further, the hydrogen storage capacity of CNT(10,0) + BH₃ complex is calculated. The estimated storage capacity of this system is in the range 6–12 wt.%.

The effectiveness of stannum (Sn²⁺) removal from aqueous solution by using magnetic biochar and functionalized multiwalled carbon nanotube (FMWCNT) was investigated. The effect of various factors, namely pH, adsorbent dosage, agitation speed and contact time was statistically studied through analysis of variance (ANOVA). Statistical analysis revealed that the optimum conditions for the highest removal of Sn²⁺ are at pH 5, dosage 0.1 g with agitation speed and time of 100 rpm and 90 min, respectively. At the initial concentration of 0.1 mg/L, the removal efficiency of Sn²⁺ using FMWCNTs was 93% and 85% with magnetic biochar. The Langmuir and Freundlich constant for both FMWCNTs and magnetic biochar were 13.397 L/mg, 18.634 L/mg and 17.719 L/mg, 25.204 L/mg, respectively. Hence, results prove that FMWCNTs are a better adsorbent with a higher adsorption capacity compared to magnetic biochar. Adsorption kinetic obeyed pseudo-second-order.

In order to create a functionalized biodegradable polymer for vascular tissue engineering application, poly(DL-lactide-co-RS-β-malic acid) (PDLLMAc) was synthesized. PDLLMAc was obtained after hydrogenolysis of poly(DL-lactide-co-RS-β-benzyl malolactonate) (PDLLMA), which was from the ring-opening polymerization of DL-lactide (DLLA) and RS-β-benzyl malolactonate (MA) using stannous octoate as catalyst. The copolymers were characterized by ¹H-NMR, FTIR, GPC and DSC. The tensile strength and water uptake of the copolymers were measured. In copolymerization, the proportion of MA in the derived copolymers was lower than that in the feeding dose, a consequence of its lower reactivity. The molecular weight of the copolymers decreased with increasing MA content. The protective benzyl groups were completely removed in hydrogenolysis. The glass transition temperature (T_g) of the protected copolymers decreased with increasing MA content. The mechanical strength test showed that the tensile strength of PDLLMA decreased while elongation increased with MA content increasing, and the tensile strength increased and elongation decreased with increasing malic acid content in PDLLMAc for the formation of hydrogen bonding. The water uptake showed that more hydrophilic malic acid adsorbed more water in PDLLMAc. In order to test the reactivity of functional pendant groups, bioactive RGD peptide was immobilized on the functionalized polymer film surface and smooth muscle cells (SMCs) were cultured on it. The results showed that the functionalized copolymer was biocompatible and could be potentially applied in vascular tissue engineering.

With reference to the Portugal-Spain Special Issue of the Journal of Porphyrins and Phthalocyanines, this highlight is mainly concerned with the contribution by the University of Aveiro group on the functionalization of the β-pyrrolic positions of triarylcorroles via cycloaddition reactions.

This review highlights synthesis procedures to obtain A₃-, cis- and trans- A₂B- and ABC-corroles. Synthesis methods from the early beginning of “corrole chemistry”, acid-catalyzed condensation methods of various building blocks (pyrrole, aldehyde, dipyrromethane, dipyrromethane-carbinol, and dipyrromethane-dicarbinol etc.), possible side reaction during Brønsted acid catalyzed reactions (scrambling), one-pot synthesis of corroles, and post-macrocyclization modification reactions of meso-substituted A₃-corroles are discussed.

In this paper, graphene oxide (GO) sheets covalently functionalized with (5,10,15,20-tetraphenyl) porphinato manganese(III) (MnTPP) has been successfully synthesized and tested as a photocatalyst for hydrogen evolution from water under UV-vis light irradiation. The obtained sample was systematically characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis, Fourier transform infrared (FTIR), and Raman spectroscopy. The results show that the MnTPP moiety has been successfully grafted on the graphene oxide surface to form MnTPP modified GO (GO-MnTPP). The fluorescence quenching and photocurrent enhancement of GO-MnTPP confirm that the rapid electrons transfer from photoexcited the MnTPP moiety to the GO sheets. The platinized GO-MnTPP exhibits enhanced photocatalytic activity for water reduction to produce hydrogen. Moreover, with the assistance of polyvinyl pyrrolidone (PVP), the photocatalytic activity is further improved because of aggregation prevention of the GO-MnTPP nanocomposite. This study provides a facile method to build porphyrin-graphene-based photocatalysts for solar energy conversion.

$N$-bridged diiron porphyrinoid complexes are powerful oxidation biomimetic catalysts. Their use as oxidation catalysts is quite recent, as it started approximately one decade ago. Many mechanistic works and elucidation of properties are conducted on simple derivatives which are not functionalized, preventing their covalent incorporation into advanced materials, even though it would expand their scope of applications. With the ultimate purpose to produce $N$-bridged diiron porphyrinoid complexes that can be incorporated into advanced functionalized materials and thereby increase the range of their utilization, we have explored synthetic strategies to prepare di- and octafunctionalised $N$-bridged diiron porphyrin complexes, either with hydroxyl or propargyl functions, which have been selected for their versatility. The considerations taken into account for the synthetic strategies are detailed and the complexes are fully characterized.

The functionalization of multiwalled carbon nanotubes (MWNTs) with β cyclodextrin (β-CD) is described. The functionalization using β-CD treatment is an environmentally friendly and nondestructive method to modify carbon nanotubes. It was observed that the degree of functionalization increases with increasing ratios of β-CD as seen from the Raman analysis. The Raman spectra also indicated that the nanotubes walls were not damaged. The presence of functional groups associated with β-CD on the functionalized MWNTs indicated that the cyclodextrin groups were found to be adsorbed at the surface of the nanotubes walls. Mixed matrix membrane (MMM) was prepared by a phase inversion process. Enhanced selectivity and permeability for CO₂ over CH₄ was observed for MMM prepared using functionalized MWNTs.

Single-walled carbon nanotubes (SWNTs) have excellent mechanical and electrical properties that have led to the proposal of many potential applications. However, SWNTs are typically grown as bundles of metallic and semiconducting tubes. This prevents their widespread application. Therefore, it is technologically critical to disperse and purify SWNTs and separate metallic and semiconducting SWNTs effectively. Recent progress and advances have been made on dispersion, separation, assemble, and control of electronic property of SWNTs by the interaction of organic molecules. This paper presents a brief review of the interaction of SWNTs with amine.

Cadmium (Cd${}^{2+}$) is one of the toxic heavy metals that is frequently used in many industrial products. The wastewater from these industries and their products contains residual cadmium that are difficult to be removed economically from the effluent. Carbon nanotubes (CNTs) were synthesized in several batches and tested for their removal efficacy with regards to cadmium removal from synthetic wastewater. Fixed catalyst chemical vapor deposition (FCCVD) reactor system was fabricated in the laboratory for the synthesis of CNTs on the powdered activated carbons (PACs). The PACs were impregnated with Fe${}^{3+}$ catalysts, and growth parameters such as the reaction time, gas flow rates and reaction temperature were optimized. The sorption capacity of the raw CNT–PAC was not satisfactory until the sorbents were functionalized which eventually led to high adsorption capacities. The surface properties of CNT–PAC were modified by oxidative functionalization using two different methods: sonication with KMnO₄ and refluxing with HNO₃ at 140${}^{\circ }$C. KMnO₄-treated CNT–PAC exhibited the highest sorption capacity for cadmium uptake which increased from 4.77mg/g (untreated CNT–PAC) to 11.16mg/g; resulting in Cd${}^{2+}$ removal efficiency from 38.87% to 98.35%.

Nanomechanical biosensors based on atomic force microscopy (AFM) cantilevers have garnered considerable attention. AFM cantilevers are devices that can detect a target either via a surface functionalization process based on immobilization through molecular adsorption, or through the selective chemical binding of a specific molecule, transforming the device into a specific biosensor. In this study, we demonstrate that functionalized AFM cantilevers could be used, in a process involving self-assembling layers, to create a homogeneous surface layer of the widely used herbicide mesotrione. Controlled experiments to evaluate its detection were performed, and binding between mesotrione and its target molecule, 4-hydroxyphenylpyruvate dioxygenase (HPPD), was evaluated using deflection curves of functionalized cantilevers interacting with mesotrione. The cantilevers worked as nanomechanical sensors inside a fluid cell device, under different concentrations of HPPD diluted in PBS. After evaluating increasing concentrations of HPPD, the deflection curves showed a clear, dose-dependent pattern. The homogeneous dispersion of mesotrione on the cantilevers was assessed by confocal microscopy, and this corroborated the functionalization method. Thus, the results obtained by this functionalized cantilever presented a high efficiency in detecting binding between HPPD and mesotrione molecules at concentrations as low as 17ng mL${}^{-1}$. In this way, as a preliminary step for a future environmental contaminants nanosensor development, the described detection method showed a suitable capability for molecular recognition at the nanoscale.