Electrochemistry and Electrocatalytic Activity of Cobaloxime Complexes

Abstract

Development of clean and renewable energy sources has emerged as one of the major interests due to the environmental issues caused by the fossil fuels. Presently a huge amount of interest has been devoted in developing the cost effective alternative energy sources and hydrogen gas has been considered as one of the substitutes for fossil fuels. Initially noble metals like Platinum was employed as a catalyst for hydrogen generation but they are costly. So, recently first row transition metal based catalysts have been utilized for the production of hydrogen gas since these metals are cost effective and earth copious. Among the first row transition metal catalysts, cobalt complexes in particular cobaloximes have been given importance as capable catalysts for hydrogen production. This review discusses about the recent advances in the electrochemistry and the various approaches employed towards the attachment of the cobaloxime complexes on the electrode surface and their electrocatalytic behaviour.

Covalent Attachment of Cobalt Bis(Benzylaminedithiolate) to Reduced Graphene Oxide as a Thin-Film Electrocatalyst for Hydrogen Production with Remarkable Dioxygen Tolerance

“…Fe, Co, and Ni are popular abundant metals for HER catalysts. ,, These metal ions are then paired with suitable ligands to tune their catalytic properties, and many corresponding catalyst systems have been reported . Important families of HER catalysts include cobaloximes, − Dubois-type catalysts, − metalloporphyrins, , metal complexes with dithiolene type ligands, − and FeFe and NiFe hydrogenase models. − There is great interest in immobilizing earth abundant transition-metal molecular catalysts on electrode surfaces, , as catalyst immobilization onto electrode surfaces adds the benefits of heterogeneous catalysis to those of molecular catalysts. The application of heterogenized molecular catalysts allows for (a) the use of less catalyst compared to homogeneous solution, (b) easy separation of the catalyst from the electrolyte solution, and (c) it also limits cross-contamination between half-cell reactions, while maintaining most of the benefits of the molecular catalyst systems.…”

g-C3N4/Chlorocobaloxime Nanocomposites as Multifunctional Electrocatalysts for Water Splitting and Energy Storage

“…Their advantages include closer simulation of the reactions of vitamin B 12 -based enzymes, facile synthesis, and more importantly, fine-tuning of the electronic and steric properties of the axial (X, B) and equatorial (L) ligands can be done effortlessly. Recently, a lot of importance has been devoted to the application of cobaloxime complexes toward photocatalytic and electrocatalytic hydrogen evolution reactions . The electrocatalytic activity of the cobaloxime complexes with MoS 2 , graphene, and MOF has been reported earlier.…”

Pyridine vs. Imidazole Axial Ligation on Cobaloxime Grafted Graphene: Hydrogen Evolution Reaction Insights

“…Akin to hydrogenase, their intrinsic extraordinary characteristics derive from their redox-active metal center (Co) and the closely lying polar oximes, coordinated in a square planar geometry. Compared to hydrogenase, a suitable electron supplement was the only missing piece, which enabled them to dominate in the molecular electrocatalytic H 2 production research field [ 2 , 3 ]. However, certain limitations, such as their insufficient aqueous solubility and long-term instability, impede their usage in realistic conditions, i.e., aqueous media.…”