Efficient water oxidation with electromodified Langmuir–Blodgett films of procatalytic [Co^III(N₂O₃)] metallosurfactants on electrodes

Abstract

Electromodified Langmuir-Blodgett films of a phenolate-rich [Co(III)(L(N2O3))H2O] metallosurfactant support water oxidation at an overpotential of 0.5 V. Gradual enhancement of catalytic activity is observed between 1 and 9 deposited layers. Upon application of a potential bias the molecular species rearranges into a catalytic layer that yields estimated turnover numbers of 54 000 ± 1500 h(-1).

Immobilization of an Amphiphilic Molecular Cobalt Catalyst on Carbon Black for Ligand-Assisted Water Oxidation

“…The ligand H 2 L OC 18 was prepared via the multistep synthetic route outlined in Scheme , which involved the functionalization of catechol with octadecyl groups to produce bis­(octadecyloxybenzene). ,,, This precursor was then nitrated, yielding 1,2-dinitro-4,5-bis­(octadecyloxy)­benzene, which was subsequently reduced to form the air-sensitive precursor 4,5-bis­(octadecyloxy)­benzene-1,2-diamine. The diamine was treated with picolinic acid to yield the ligand N , N ′-[4,5-bis­(octadecyloxy)-1,2-phenylene]­dipicolineamide, H 2 L OC 18 …”

“…Produced by the incomplete combustion of petrochemicals, carbon black (CB) has been used as a solid support along with Nafion to drive catalytic water oxidation. − As such, we hypothesized that CB can be functionalized with an amphiphilic metal complex and that van der Waals interactions between the substrate and complex will lead to more robust water oxidation catalysts. Therefore, similar to other systems that we reported in the recent past, ,− we designed a new ligand with two octadecyloxy groups incorporated into the backbone. These alkoxy groups play important functions: (i) they serve as hydrophobic backbones to anchor the molecule onto CB, and (ii) they lower the oxidation potential required for water oxidation.…”

“…Recent efforts have focused on anchoring molecules onto conductive solid supports in an attempt to favor the high-valent [M n L] n + product, enhancing the robustness of catalysts and favoring water splitting. − We have recently shown that physisorbed Langmuir–Blodgett films of a procatalytic phenolate-rich cobalt complex are effective on fluorine-doped tin oxide . The resulting modified electrode is an excellent water oxidation catalyst with an overpotential of 0.5 V. However, structural rearrangement takes place after a potential bias is applied.…”

A methodological review on material growth and synthesis of solar-driven water splitting photoelectrochemical cells

“…For example, a lm formed through Langmuir-Blodgett was also used to form water splitting electrodes. 80 However, needless to say, just a single material synthesis or growth method alone cannot dene the PEC cell. Even the simplest water splitting photoanode introduced in this article, for example, HVPE-grown GaSb x P 1Àx , requires an IrO 2 thin-lm which is prepared by a solution-based process for a properly working photoanode.…”

Immobilization of “Capping Arene” Cobalt(II) Complexes on Ordered Mesoporous Carbon for Electrocatalytic Water Oxidation

“…Recently, research efforts have focused on the preparation of supported electrocatalysts by anchoring molecular catalysts directly to an electrode or to a carbon support using covalent and noncovalent attachment methods. − Several examples have been reported for the synthesis of cobalt-heterogenized catalysts for water oxidation via van der Waals interactions between a cobalt complex with long alkyl chains and fluorine-doped tin oxide (FTO) or carbon electrodes (see, for example, g in Scheme ). − Supported Co II phthalocyanine complexes are efficient molecular water oxidation electrocatalysts at pH 7 when physiosorbed onto FTO ( h , Scheme ) or at basic pH (1 M KOH) when π–π-stacked onto carbon nanotubes . Investigations of cobalt porphyrin complexes physiosorbed onto FTO ( i , Scheme ) demonstrated that the formation of a CoO x film on the electrode is responsible for the observed catalytic water oxidation activity .…”