Mn oxide as a kinetically dominant “true” catalyst for water oxidation

Nature uses an Mn cluster for water oxidation, and thus, water oxidation using Mn clusters is interesting when used in artificial water-splitting systems. An important question is whether an Mn cluster is a true catalyst for water oxidation or not. Herein, an Mn–K cluster was investigated for electrochemical water oxidation to find the true and the kinetically dominant catalyst using X-ray absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and electrochemical methods. The experiments showed that conversion into nanosized Mn oxide occurred for the cluster, and the nanosized Mn oxides are the true catalyst for water oxidation

Electrochemical alcohols oxidation mediated by N-hydroxyphthalimide on nickel foam surface

Alcohol to aldehyde conversion is a critical reaction in the industry. Herein, a new electrochemical method is introduced that converts 1 mmol of alcohols to aldehydes and ketones in the presence of N-hydroxyphthalimide (NHPI, 20 mol%) as a mediator; this conversion is achieved after 8.5 h at room temperature using a piece of Ni foam (1.0 cm2) and without adding an extra-base or a need for high temperature. Using this method, 10 mmol (1.08 g) of benzyl alcohol was also successfully oxidized to benzaldehyde (91%) without any by-products. This method was also used to oxidize other alcohols with high yield and selectivity. In the absence of a mediator, the surface of the nickel foam provided oxidation products at the lower yield. After the reaction was complete, nickel foam (anode) was characterized by a combination of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and spectroelectrochemistry, which pointed to the formation of nickel oxide on the surface of the electrode. On the other hand, using other electrodes such as Pt, Cu, Fe, and graphite resulted in a low yield for the alcohol to aldehyde conversion

Role of decomposition products in the oxidation of cyclohexene using a manganese(III) complex

Metal complexes are extensively explored as catalysts for oxidation reactions; molecular-based mechanisms are usually proposed for such reactions. However, the roles of the decomposition products of these materials in the catalytic process have yet to be considered for these reactions. Herein, the cyclohexene oxidation in the presence of manganese(III) 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride) (1) in a heterogeneous system via loading the complex on an SBA-15 substrate is performed as a study case. A molecular-based mechanism is usually suggested for such a metal complex. Herein, 1 was selected and investigated under the oxidation reaction by iodosylbenzene or (diacetoxyiodo)benzene (PhI(OAc)2). In addition to 1, at least one of the decomposition products of 1 formed during the oxidation reaction could be considered a candidate to catalyze the reaction. First-principles calculations show that Mn dissolution is energetically feasible in the presence of iodosylbenzene and trace amounts of water

challenges for biomimetic water oxidation

Herein, we report the synthesis, characterization, crystal structure, density functional theory calculations, and water-oxidizing activity of a pivalate Mn–Ca cluster. All of the manganese atoms in the cluster are Mn(IV) ions and have a distorted MnO6 octahedral geometry. Three Mn(IV) ions together with a Ca(II) ion and four-oxido groups form a cubic Mn3CaO4 unit which is similar to the Mn3CaO4 cluster in the water-oxidizing complex of Photosystem II. Using scanning electron microscopy, transmission electron microscopy, energy dispersive spectrometry, extended X-ray absorption spectroscopy, chronoamperometry, and electrochemical methods, a conversion into nano-sized Mn-oxide is observed for the cluster in the water-oxidation reaction

The effect of sex education on patients and their spouses satisfaction after myocardial infarction

Background & Objective: Myocardial infarction is one of the most common coronary artery diseases. One of the educational needs of patients, is how to perform sexual activities. Unfortunately, this issue is not being taught to patients, leading to problems in patients and their partners. This study was aimed to determine the effect of sex education on patients and their spouses› satisfaction after myocardial infarction. Method: This Quasi-experimental, non-randomized study was performed on 60 patients with myocardial infarction and their spouses in the city of Yazd whom were divided into two groups of experimental and control (60 in each group),in the year 1392. The main method of this study was the education and preparation of nurses and then educating patients by trained nurses and to assess sexual satisfaction based on the standard Larson›s questionnaire. The data were then statistically analyzed using SPSS version 16 using paired, independent t-test. Results: The average sexual satisfaction of patients in the experimental group before the intervention was 81.93 ± 12.47 and after the intervention 82.50 ± 12.57 While in the control group before the intervention the average satisfaction was 83.10 ± 17.36 and after 6 weeks 75.30 ± 15.42. Also the mean sexual satisfaction of partners in the test group before and after the intervention was 81.30 ± 12.47 and 82.07 ± 12.28 respectively. In the control group before the intervention, the average score was 82.50 ± 17.21 and after intervention it was 74.57 ± 15.30. There was significant difference between patients and spouses› sexual satisfaction scores in the experimental and control groups before and after the intervention (P=0.001). Conclusion: Sex education increased the sexual satisfaction among the tested group. Therefore, it is suggested to include programs in order to prepare nurses in terms of sex education of patients and their spouses in cardiac intensive wards

Strong enhancement of the chemiluminescence of the Cu(II)-H2O2 system on addition of carbon nitride quantum dots, and its application to the detection of H2O2 and glucose

The authors report that carbon nitride quantum dots (CN QDs) exert a strong enhancing effect on the Cu(II)/H2O2 chemilumi-nescent system. Chemiluminescence (CL) intensity is enhanced by CN QDs by a factor of similar to 75, while other carbon nanomaterials have a much weaker effect. The possible mechanism of the effect was evaluated by recording fluorescence and CL spectra and by examining the effect of various radical scavengers. Emitting species was found to be excited-state CNQDs that produce green CL peaking at 515 nm. The new CL system was applied to the sensitive detection of H2O2 and glucose (via glucose oxidase-catalyzed formation of H2O2) with detection limits (3 sigma) of 10 nM for H2O2 and 100 nM for glucose. The probe was employed for glucose determination in human plasma samples with satisfactory results

Nanosized silver bromide: an efficient catalyst for alcohol oxidation in the presence of a multinuclear silver complex

Upon investigating a silver-based complex for the alcohol oxidation reaction, we found AgBr as a new and efficient catalyst for the reaction in the presence of oxone (2KHSO(5)KHSO(4)K(2)SO(4)). The catalyst was characterized by scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy, dynamic light scattering, X-ray diffraction, chronoamperometry, X-ray photoelectron spectroscopy, and liquid chromatography-electrospray ionization mass spectrometry. We propose that nanosized silver bromide can be used as a catalyst for the oxidation of alcohol to aldehyde in the presence of oxone (2KHSO(5)KHSO(4)K(2)SO(4)) as an oxidant

Pomegranate (Punica granatum) Peel Extract as a Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

The inhibition effect of pomegranate peel extract (PPE) on the corrosion of mild steel in hydrochloric acid (HCl) solution was investigated. The polarization, mass loss, and electrochemical impendence techniques were used to evaluate the corrosion inhibition performance of the pomegranate peel extract. The results revealed that PPE acts as a corrosion inhibitor in HCl solution. The inhibition efficiency increased with the increase of extract concentration. The inhibition action was attributed to the adsorption of the chemical compounds present in the extract solution, on mild steel surface

Water oxidation by Ferritin: A semi-natural electrode

Water oxidation by Ferritin: A semi-natural electrod

Photochemical deposition of silver on Fe2O3 nanotubes prepared by anodization and exploring their photoelectrochemical activity

Photochemical deposition of silver on Fe2O3 nanotubes prepared by anodization and exploring their photoelectrochemical activit