Double-layer capacitance characterization of porphyrin-modified graphite electrodes

Porphyrin-modified graphite electrodes were manufactured and evaluated in terms of their double-layer capacitance. The highest value, of 14.017 mF/cm2 , was obtained for the electrode resulted by drop-casting a layer of 5,10,15,20-tetrakis(4-methoxy-phenyl)-porphyrin from benzonitrile on graphite support. Since a high double-layer capacitance value is characteristic of supercapacitors, out of the investigated samples, this electrode is the most likely to find application in their field

5-(4-Pyridyl)dipyrromethane-silica sol synthesis and luminescent properties

Methodologies for the immobilization and characterization of 5(4-pyridyl)dipyrromethane into silica gel are described. The corresponding spectroscopic, thermal, and photochemical properties are used for their characterization and study

Porphyrin based-systems for the detection of recoverable metals from Li-Ion batteries : mini-review

The collection and recycling of metals, especially heavy metals, from all types of batteries is a major requirement of European Countries. Market studies highlighted that in the rechargeable battery field, lithium batteries are environmental friendly alternatives to the more polluting Ni-Cd batteries. Although lithium is not expected to bioaccumulate and its human and environmental toxicity are low, one source of lithium with impact to the environment is spent lithium batteries, due to the large variety of Li salts incorporated in polymer electrolyte membranes. Concerning to cathode, new trends are based on nanostructured lithium iron and manganese phosphate. Whatever are the metals involved in the cathode of batteries (Co-NiMn-Fe) the problem of controlling the efficiency of metals recovery is implying the use of sensor devices. In this paper we are concerned on porphyrin -based sensor devices for the rapid and accurate detection of Li, Ni, Mn

Electrochemical characterization of PVC-Pt(II) porphyrin-membrane

The maximum water volume fraction absorbed by membrane based on Pt(II)- 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) in poly(vinyl)chloride (PVC) matrix applied on iron substrate is 0.3 % and the permeability is 7.6×10−12 m 2 s −1 . After 24 h immersion in the 0.5 M 4-morpholinoethanesulfonic acid (MES) solution of pH = 5.5, the Nyquist representation of impedance data shows diffusion into the membrane of electrolytes from the buffer solution, causing a decrease of the membrane electric resistance, but no delamination was observed for immersion longer than 48 h. Furthermore, the coating resistance is still close to ~16000 ohm.cm−2 after 25 hours. This recommends this membrane as good material in potentiometric sensors design

Detection of phosphine derivates using metalloporphyrins

Starting from the knowledge that phosphine derivatives exhibit medium/high toxicity, in this study we focused on the behavior of Co(II)- 5,10,15,20-tetratolyl-porphyrin (CoTTP) and Mn(III)-5,10,15,20-tetraphenyl-porphyrin chloride (MnTPPCl) as active UV-vis chromophores for the detection of triphenylphosphine oxide (LC50=12.2µg/mL, LC90=29.5µg/mL). The increase of triphenylphosphine oxide concentration generates the hypochromic effect on the Soret bands of the two metalloporphyrins. A comparison regarding the efficiency of the two metalloporphyrins in detecting phosphine derivatives was done

Structured composites between MnTa2O6 and porphyrins: Influence of the number of carboxylic groups grafted on porphyrins on the capacity to inhibit corrosion of steel

New sandwich type materials based on MnTa2O6 and porphyrins mono- and tetra-substituted with –COOH groups, namely: (tetrakis-(4-carboxy-phenyl)-porphyrin and 5-(4-carboxy-phenyl)-10,15,20-tris-phenyl-porphyrin) have been synthesized and studied to assess the importance of its corrosion inhibition ability on with regard to its of steel the number of –COOH anchors. Morphological investigations on thin films have been carried out by atomic force microscopy. The inhibition of corrosion has been evaluated by open circuit potential measurements and potentiodynamic polarization technique with Tafel representation, after drop-casting deposition onto carbon steel in 0.1M HCl media. The inhibition efficiency of the novel sandwich-type materials based on pseudo-binary oxide MnTa2O6 and tetrakis-(4-carboxy-phenyl)-porphyrin or 5-(4-carboxy-phenyl)-10,15,20-tris-phenyl-porphyrin is in the range 76-86% for tetra substituted porphyrin and 84-95% for the mono-COOH substituted porphyrin

Zn-metalloporphyrins containing pyridyl groups and their comparative capacity to coordinate hexachloroplatinic acid

Two Zn-metalloporphyrins, both containing at least one-pyridyl group, were studied regarding their capacity to complex hexachloroplatinic acid comprised in leaching solutions and resulted after hydrometallurgical processes on spent automotive catalysts. The number of pyridyl groups and the steric and electronic influences from surrounding groups determine a different type of coordination with the hexachloroplatinic acid from solution, and surprisingly, although containing only one group of basic pyridyl, the unsymmetrical Zn(II)- 5-pyridyl-10,15,20-tris-(3,4-di-methoxy-phenyl)-porphyrin had a removal capacity of 98% higher than that of Zn(II)-meso-tetrakis-pyridylporphyrin, substituted with four pyridyl groups, but with only a removal capacity of 84 %