Single-and double transition metal atoms anchored C2N as a high-activity catalyst for CO oxidation: A first-principles study.

The oxidation of CO has attracted great interest in recent years due to its important role in enhancing the catalyst durability in fuel cells and solving the growing environmental problems caused by CO emissions. Consequently, the catalytic oxidation of CO at double non-noble metal atoms anchored C2N is investigated using density functional theory (DFT) computations. All the screened Ti@C2N and Ti2@C2N are thermodynamically stable based on their binding energy calculations. The electronic characteristics, the natural bond orbital analyses (NBO), Frontier orbital, statistical thermodynamics, projected densities of states (PDOS) characteristics, non-covalent interactions (NCI), and quantum theory of atoms in molecules (QTAIM) descriptors of these systems have been examined to analyze the interaction process. Our comparative study suggested that the newly predicted double-atom catalyst (Ti2@C2N) is highly active for CO oxidation, which is a useful guideline for further development. The calculated static first-order hyperpolarizability (ßo) illustrated that the double-atom catalyst under investigation can be considered a potential candidate for non-linear optical behavior and could be used for NLO applications. CO oxidation on Ti2@C2N along the Eley-Rideal (ER) mechanism with a low energy barrier of 0.16 eV, which is smaller than the maximum energy barrier (0.73 eV) of CO oxidation along the Langmuir-Hinshelwood (LH) mechanism. Consequently, the ER mechanism is more favorable both thermodynamically and dynamically. This work can provide useful insights and guidelines for future theoretical and experimental investigations to promote the design and development of highly effective and low-cost non-precious-metal Ti2@C2N nanocatalysts towards CO oxidation at ambient temperature.

Tenability on schiff base Hydrazone derivatives and Frontier molecular orbital.

Context hydrazine compounds based on 1,3,5-triazine were synthesised and their molecular structures were characterised by elemental analysis, Electronic, IR and 1H NMR spectra. The spectral behaviour of the newly prepared compounds in organic solvents of different polarities was extensively studied and correlated to the molecular structure. In this study, 1,3,5-Triazine derivatives (L1, L6, L7, L8) have been subjected to theoretical studies using the Semi-empirical PM3 quantum chemical method. The physical-chemical properties of some Hydrazone derivatives are determined theoretically. The molecular geometry, the Highest Occupied Molecular Orbital (HOMO) - Lowest Unoccupied Molecular Orbital (LUMO) energy gap, molecular hardness (η), ionisation energy (IE), Electron affinity and total energy were analysed, and applications as biological effects were done.

The effect of central transition metals and electron-donating substituent on the performances of dye/TiO2 interface for dye-sensitized solar cells applications.

Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) approaches were applied to explore the effect of central transition metals and the dye/TiO2 interface on dye-sensitized solar cell (DSSC) performance and supply a promising way to estimate and screen possible candidates for DSSC applications. The interaction properties, bonding characteristics, sensitized mechanisms, charge transfer, frontier molecular orbitals, energy gap, partial densities of states (PDOS), non-covalent interactions (NCI), and electronic absorption spectra were examined and analyzed to provide the photovoltaic characteristics of Sc, Cu, and Ti tetrasulfonic acid phthalocyanine sensitizer@TiO2 interface in both gas phase and polar solvent as acetonitrile. The interfacial of TiPc-(SO3H)4 with TiO2, which facilitates the driving force for the electron injection of photosensitizers (ΔGinj), increases the charge separation, open-circuit voltage (Voc), and high light-harvesting efficiency (LHE) values. However, minimize the charge recombination, lifetime of the excited state (τ), regeneration driving force (ΔGreg). Our results reveal that TiPc-(SO3H)4@TiO2 is superior to those of ScPc-(SO3H)4, CuPc-(SO3H)4, TiPc-(SO3H)4 and Pc-(SO3H)4/TiO2, indicating the novel TiPc-(SO3H)4@TiO2 interface could be promising candidates for DSSC photovoltaic devices performance. In addition, the static mean polarizability and first hyperpolarizability of all six dyes elucidated that the TiPc-(SO3H)4@TiO2 interface can be regarded as a potential performer in non-linear optical (NLO) properties. These theoretical identifications may provide novel perspectives and instructions for future experimental researchers to promote the synthesis and application of TiPc-(SO3H)4@TiO2 interfaces to improve the photo-to-current conversion efficiency.

Enhanced hydrogen storage performance of Li and Co functionalized h-GaN nanosheets: DFT study.

Based on the density functional theory (DFT) computations, we investigated the hydrogen storage performances of alkali metal (Li) and transition metal (Co) decorated the defective GaN nanosheets. Fundamental aspects including the interaction properties, bonding characteristics, adsorption ability, frontier orbital, HOMO-LUMO energy gaps, natural bond orbital (NBO) analysis, projected densities of states (PDOS) and statistical thermodynamic stability have been demonstrated to analyze the interaction properties of H2 molecules. As a theoretical strategy, non-covalent interactions (NCI) and the atoms in molecules (QTAIM) descriptors were performed to depict weak interactions. The LiN-GaN and CoN-GaN systems and the H2 uptake capacity revealed to be 7.78% and 5.55%, respectively. Our results demonstrated that H2 molecules are introduced sequentially on the Li and Co that functionalized both sides of VN-GaN nanosheets yielded the gravimetric densities up to 8.158% (2Co-VN-GaN) that well above the gravimetric DOE achieve. The 2LiN-GaN and 2CoN-GaN are energetically more effective for the H2 adsorption, stable and preferred than pristine GaN nanosheet. Additionally, two binding mechanisms including polarization of the hydrogen molecules and σ orbitals hybridization of H2 molecules have been investigated to explain the interaction of H2 molecules. The hydrogen desorption enthalpy and desorption temperatures of hydrogen molecules, indicating the H2 molecules are easy to desorb from Li and Co decorated defective GaN nanosheets. These results suggest the possibility of an excellent and promising nanostructural material to improve the performance of hydrogen storage for in fuel cells application at ambient temperature.

Use of rice straw and radiation-modified maize starch/acrylonitrile in the treatment of wastewater.

Graft copolymerization of acrylonitrile onto maize starch by a simultaneous irradiation technique using gamma-rays as the initiator was studied with regard to the various parameters of importance: the monomer-to-maize starch ratio and total dose (kGy). The water absorption of the modified maize starch was measured. The starch modified by acrylonitrile gives low water absorbance. Conversion of the copolymer to the amidoxime form gives high swelling. The gel (%) and the grafting efficiency were measured. An investigation was carried out to study the adsorption of basic violet 7, basic blue 3, direct yellow 50 and acid red 37 from aqueous solutions by the water-insoluble modified starch containing amidoxime groups and rice straw. The effects of initial pH of the solution, pollutant concentration and treatment time on the adsorption were studied and it was found that the maximum adsorption was at 1:2 (starch/acrylonitrile) at irradiation dose 30 kGy.

Regulation of rubratoxin-B biosynthesis: assessment of role of gamma-irradiation, pH and carbohydrates.

The maximum rubratoxin-B yield was obtained at pH 5.5,, and by increasing the initial pH to near neutrality the yield decreased for both yeast extract sucrose (YES) and Sabouraud dextrose yeast extract (SDYE) media, but the concentration of mycotoxin was higher in YES medium. The rubratoxin-B yield from Penicillium purpurogenium decreased with increasing gamma-irradiation, and at 1.0 kGy no mycotoxin was detected at any pH values. In both the unirradiated and irradiated P. purpurogeniium cultures, as the rubratoxin-B synthesis increased from 46 to 72 h, the lipid content decreased. The concentration (mmoles/g dry wt mycelium) of puridine nucleotides in the mycelium of P. purpurogenium during growth in YES and SDYE media may be a factor in rubratoxin-B synthesis. An elevated NADPH/ NADP ratio favours fatty acid synthesis whereas a depressed NADPH/NADP ratio favours mycotoxin formation. The gamma-irradiation played a role in the regulation of rubratoxin-B biosynthesis.

Hydantoin immunosuppression clinical study.

A study was conducted on 51 epileptic patients divided into two groups. Group 1: 20 patients without anticonvulsant treatment for at least two years, and group II: 31 patients receiving phenytoin in a dose of 300 mg/24 hr for at least 4 months. A group of normal and blood donor subjects were used as control. The serum concentrations of IgA and IgM were significantly decreased in the phenytoin treated patients in comparison with control. Non-treated epileptics showed a significant decrease of IgA level in comparison with control. It was suggested that phenytoin treatment suppresses the normal function of the humoral immune response and that epilepsy may be a contributing factor.

Liver injury associated with N-acetylcysteine administration.

90 adult male albino rats, were divided into two groups each comprising 45 rats out of which 15 were used as controls. N-acetylcysteine was given orally in a doses of 300 and 600 mg/Kg body weight respectively for three weeks. At the end of each week 10 rats from each experimental group as well as 5 rats from control animals were sacrificed and biochemical and pathological studies for hepatic functions and structure were performed. NAC in the high dose group induced significant changes in the liver function tests suggestive of liver dysfunction and damage. Histopathological studies revealed cell ballooning portal dilatation with round cell infiltration, portal tract fibrosis and proliferations. It was concluded that NAC in small dose is safe and can be used, while in large dose it has a hepatotoxic potential.

Effect of lead nitrate administration on liver and kidney structure in rats.

A study was conducted on male albino rats ranging in weight between 150-180 g. The animals were given a single and repeated intravenous injections of lead nitrate (100 mu mol/kg body weight) once every 10 days for one, two, three and four injections respectively. Histopathological examination revealed that induction of hepatic and renal cellular proliferation without cellular necrosis occurred with single and repeated administration. No biochemical alterations in liver function tests and serum creatinine were detected throughout the whole period of study. These changes are suggested to be an adaptive response rather than a toxic effect.