Related Experiment Video
Updated: May 7, 2026

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
A computational study of the mechanism of hydrogen evolution by cobalt(diimine-dioxime) catalysts
Anirban Bhattacharjee1, Eugen S Andreiadis, Murielle Chavarot-Kerlidou
1Dynamo Team, DYNAMOP Group, UMR 5075, Université Grenoble 1, CNRS, CEA, Institut de Biologie Structurale "Jean-Pierre Ebel", 41 rue Jules Horowitz, 38027 Grenoble Cedex 1 (France).
Abstract:
Cobalt(diimine-dioxime) complexes catalyze hydrogen evolution with low overpotentials and remarkable stability. In this study, DFT calculations were used to investigate their catalytic mechanism, to demonstrate that the initial active state was a Co(I) complex and that H2 was evolved in a heterolytic manner through the protonation of a Co(II)-hydride intermediate. In addition, these catalysts were shown to adjust their electrocatalytic potential for hydrogen evolution to the pH value of the solution and such a property was assigned to the presence of a H(+)-exchange site on the oxime bridge. It was possible to establish that protonation of the bridge was directly involved in the H2-evolution mechanism through proton-coupled electron-transfer steps. A consistent mechanistic scheme is proposed that fits the experimentally determined electrocatalytic and electrochemical potentials of cobalt(diimine-dioxime) complexes and reproduces the observed positive shift of the electrocatalytic potential with increasing acidity of the proton source.
More Related Videos
08:40Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
Published on: December 6, 2021
06:32A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions
Published on: August 17, 2016
Related Concept Videos
Catalysis
Catalysis
Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Heterogeneous Catalysis
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.