Iron and Cobalt Corroles in Solution and on Carbon Nanotubes as Molecular Photocatalysts for Hydrogen Production by Water Reduction

Abstract

Abstract:Here we report the use of cobalt and iron corrole complexes as catalysts of H2O reduction to generate H2. Electro and photocatalysis has been used in the case of dissolved corroles for water reduction with inspiring results. Carbon nanotubes doped with corroles were used as photo-electrochemical catalysts allowing getting very low overpotential values and increased hydrogen production, achieving incredibly high turnover numbers and turnover frequencies of ca. 10 7 and 10 5 , respectively. Through this last process we were able to obtain 1mmol of H2 by using minuscule amounts of catalyst, in the order of pictograms. The reactions can be carried out in water, without the need of organic solvents. Remarkably, the photoelectrochemical catalytic efficiency was increased by five orders of magnitude when adsorbing the molecular catalysts onto carbon nanotubes.

Cobalt Corroles as Electrocatalysts for Water Oxidation: Strong Effect of Substituents on Catalytic Activity

“…Because of this, the overpotential for certain oxidation reactions may be reduced while the kinetic rate of reduction reactions may be increased . Corrole metal complexes have been shown to catalyze reactions of synthetic value such as hydroxylation, epoxidation, or cyclopropanation. , They have also been used in energy conversion reactions such as proton, − oxygen, , or carbon dioxide reduction, , as well as water oxidation. , …”

Electrocatalytic hydrogen evolution using triaryl corrole cobalt complex

“…Complex 1 exhibited a better performance than our previously reported cobalt corrole Co(TECC)(Py) 2 and Co(TNPC)PPh 3 but was less active than Fe(TPFC)Cl . All synthesized cobalt corroles exhibited a HER TOF similar to those cobalt corroles with photo‐electrochemical catalysts such as Co(TNPC), Co(TPC), and Co(TDPC) in the homogeneous system . The cobalt aminophenyl‐substituted corrole Co(BAPC)Py 2 also exhibited a good HER activity in the homogeneous system at 250 mV overpotential with a HER rate constant of 952 s −1 .…”

Corroles at work: a small macrocycle for great applications

“…35, dispersed on MWCNTs as catalysts. 74 In this work, terphenyl was exploited as a photosensitizer and triethylamine as a sacrificial electron donor. The photocatalytic production of hydrogen was first carried out by dissolving corrole, terphenyl and triethylamine in dioxane under UV irradiation.…”

“…35 Molecular structures of the A 3 corroles dispersed on MWCNTs. 74 addition. The mechanism of the reaction followed different steps, as described below:…”

“…Fig 74. Principal elements used in medical imaging (MRI, PET, SPECT and Optical Imaging) [187][188][189][190].…”