Double-layer capacitance study of a nickel phosphite/prophryn-modified graphite electrode with watersplitting catalytic properties

An electrode exhibiting water-splitting catalytic properties was manufactured by applying a combination between Ni11(HPO3)8(OH)6 and 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin on graphite substrate. The specimen was coded GNiPh-TMeOPP and its double-layer capacitance was investigated. The obtained value of 7.475 mF/cm2 is higher than the ones determined for the unmodified graphite support and for the nickel phosphite-based graphite electrode. This result indicates that GNiPh-TMeOPP is the most likely to find application in the field of supercapacitors

Electrochemical durability of magnetite and birnessite modified electrodes with potential application in water splitting

Graphite electrodes were modified with compositions containing either Fe3O4 or δ-MnO2, and their electrochemical durability was investigated using the cyclic voltammetry method. Experimental results indicate that the most stable electrode is the one modified with the composition containing magnetite and Vulcan carbon, when exposed to electrochemical potentials in the anodic domain. Given this result and the potential values at which oxygen is evolved on the electrode, it has the prospect to find application in the water splitting domain

The electrocatalytic activity of YMnO3-based electrodes for the O2 and H2 evolution reactions in a strong alkaline medium

YMnO3 perovskites synthesized using the sol-gel method were studied regarding their electrocatalytic properties for the O2 and H2 evolution reactions (OER and HER) in a strong alkaline medium. The highest activity was observed during HER experiments, especially for the electrodes manufactured using suspensions containing Nafion, Carbon Black and either Co2+ doped YMnO3 or Sn2+ doped YMnO3. For these samples, the HER overpotential value at i = ─10 mA/cm2 was 0.83 V. The main conclusions are the following: (a) the inclusion of Carbon Black into the electrode manufacturing process improved the HER catalytic activity of all perovskite-modified electrodes and (b) the HER activity of the samples modified with the catalysts, Nafion and Carbon Black was similar despite the different temperatures applied during perovskite synthesis

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

Preliminary water splitting studies on Ag and graphite modified porous structures, as such or decorated with Pt particles

Porous materials were obtained using polyether foam modified with Ag nanowires and graphite paste. Some of those modified porous structures were decorated with Pt particles via double step chronoamperometry. All porous materials were investigated in terms of their electrocatalytic activity for the oxygen and hydrogen evolution reactions (OER and HER) in alkaline medium, after they were inserted into supports made from sintered graphite (for the OER experiments) or Ag wire (for the HER experiments). Electrochemical stability tests were also performed. The results of the OER and HER experiments show that the most catalytically active porous structure is the one modified with graphite paste and Pt particles. Stability tests data show that the porous electrode based on this structure is very stable

Morphological investigation of calcium phosphates electrodeposited on Ti in the presence of tartaric acid

The electrochemical deposition method was employed to deposit calcium phosphates on Ti substrates in the presence of different concentrations of tartaric acid. Scanning electron microscopy was used to investigate the morphology of the obtained specimens. The micrographs indicate that as the tartaric acid concentration increases, the size and number of calcium phosphate irregular structures increases as well. At the highest concentration a new morphology is evidenced, represented by flat ordered structures with high aspect ratio

Electrochemical synthesis of poly-3-aminophenylboronic acid in sulfuric acid solution

Sensors based on the complexation of boron groups with diols are an attractive alternative to detection of biologic compounds in particular dopamine. The electropolymerisation of 3- aminophenylboronic acid (APBA) in aqueous solutions on Pt electrodes has been investigated. The obtained poly-3-aminophenylboronic acid is used for the potentiometric detection of dopamine