Synthesis and optimisation of IrO2 electrocatalysts by Adams fusion method for solid polymer electrolyte electrolysers

IrO2 as an anodic electrocatalyst for the oxygen evolution reaction (OER) in solid polymer electrolyte (SPE) electrolysers was synthesised by adapting the Adams fusion method. Optimisation of the IrO2 electrocatalyst was achieved by varying the synthesis duration (0.5 – 4 hours) and temperature (250 - 500°C). The physical properties of the electrocatalysts were characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction (XRD). Electrochemical characterisation of the electrocatalysts toward the OER was evaluated by chronoamperometry (CA). CA analysis revealed the best electrocatalytic activity towards the OER for IrO2 synthesised for 2 hours at 350oC which displayed a better electrocatalytic activity than the commercial IrO2 electrocatalyst used in this study. XRD and TEM analyses revealed an increase in crystallinity and average particle size with increasing synthesis duration and temperature which accounted for the decreasing electrocatalytic activity. At 250°C the formation of an active IrO2 electrocatalyst was not favoured

1-(3,5-Dimethyl-1H-pyrazol-1-yl)-3-phenyl­isoquinoline

The mol­ecular conformation of the title compound, C20H17N3, is stabilized by an intramolecular C—H⋯N inter­action. The crystal structure shows inter­molecular C—H⋯π inter­actions. The dihedral angle between the isoquinoline unit and the phenyl ring is 11.42 (1)° whereas the isoquinoline unit and the pendent dimethyl pryrazole unit form a dihedral angle of 50.1 (4)°. Furthermore, the angle between the mean plane of the phenyl ring and the dimethyl pyrazole unit is 47.3 (6)°

1-(4-Chloro-3-fluoro­phen­yl)-2-[(3-phenyl­isoquinolin-1-yl)sulfan­yl]ethanone

In the title compound, C23H15ClFNOS, the isoquinoline system and the 4-chloro-3-fluoro­phenyl ring are aligned at 80.4 (1)°. The dihedral angle between the isoquinoline system and the pendant (unsubstituted) phenyl ring is 19.91 (1)°

Methyl 2-methyl-2H-1,2,3-triazole-4-carboxyl­ate

In the title compound, C5H7N3O2, all non-H atoms lie in a common plane, with a maximum deviation of 0.061 (2)° for the ester methyl C atom. The structure is stabilized by inter­molecular C—H⋯O hydrogen bonds

3-(4-Methoxy­phen­yl)-1H-isochromen-1-one

The asymmetric unit of the title compound, C16H12O3, contains two crystallographically independent mol­ecules. The isochromene ring system is planar (maximum deviation 0.024 Å) and is oriented at dihedral angles of 2.63 (3) and 0.79 (3)° with respect to the methoxy­benzene rings in the two independent mol­ecules

1,3-Dimethyl-2,6-diphenyl­piperidin-4-one

In the title moleclue, C19H21NO, the 4-piperidone ring adopts a chair conformation in which the two benzene rings and the methyl group attached to C atoms all have equatorial orientations. In the crystal structure, centrosymmetric dimers are formed through weak inter­molecular C—H⋯O hydrogen bonds [the dihedral angle between the aromatic rings is 58.51 (5)°]

Cobalt and nickel uptake by silica-based extractants

The pKas of ethyl/butyl phosphonate silica (EBP-Si) have been determined, and the removal of cobalt and nickel from solution was investigated as a function of various parameters and compared with those of Purolite S950. pH uptake experiments suggested a combination of ion exchange and acid dissociation of the surface occurring. Isotherm data, fitted using the Langmuir and Dubinin–Radushkevich (D-R) models, indicated that stronger complexes formed with S950 than with EBP-Si. Kinetic data, fitted using a pseudo-second-order model, suggested that the rate-determining process is the reaction of metal ions with the chelating functionality of the resin. Uptake by EBP-Si is two to three times faster than that on S950

3-Acetyl-6-chloro-1-ethyl-4-phenyl­quinolin-2(1H)-one

In the title compound, C19H16ClNO2, the dihedral angle between the plane of the phenyl substituent and 3-acetyl­quinoline unit is 75.44 (5)°. The crystal structure is stabilized by inter­molecular C—H⋯O hydrogen bond