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06:32
A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions
Published on: August 17, 2016
Hydrogen generation catalyzed by fluorinated diglyoxime-iron complexes at low overpotentials
Michael J Rose1, Harry B Gray, Jay R Winkler
1Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States.
Journal of the American Chemical Society
|May 16, 2012
Summary
Iron complexes with fluorinated ligands show promising electrocatalytic activity for hydrogen generation. A modified complex efficiently produces H(2) at relatively positive potentials, outperforming others.
Area of Science:
- Inorganic Chemistry
- Electrochemistry
- Catalysis
Background:
- Iron complexes with fluorinated ligands offer tunable redox properties.
- Electrocatalytic hydrogen generation is crucial for sustainable energy solutions.
- Understanding reaction mechanisms is key to improving catalyst efficiency.
Purpose of the Study:
- To synthesize and characterize novel iron complexes with fluorinated ligands.
- To evaluate the electrocatalytic performance of these complexes for hydrogen production.
- To elucidate the reaction mechanisms involved in H(2) generation.
Main Methods:
- Synthesis of difluoroborated and monofluoroborated iron complexes.
- Electrochemical characterization using cyclic voltammetry.
- Electrocatalytic testing for H(2) generation.
- Computational simulations to study reaction mechanisms.
Main Results:
- Difluoroborated iron complex [(dAr(F)gBF(2))(2)Fe(py)(2)] electrocatalyzes H(2) generation at -0.9 V vs SCE with a turnover frequency (TOF) of ~20 s(-1).
- Monofluoroborated complex [(dAr(F)g(2)H-BF(2))Fe(py)(2)] shows enhanced performance with a TOF of ~200 s(-1) at -0.8 V.
- Simulations indicate rate-limiting protonation steps for both complexes, with different mechanistic pathways (Fe(0) vs Fe(I) intermediates).
Conclusions:
- The monofluoroborated iron complex demonstrates superior electrocatalytic activity and operates at more positive potentials.
- Fluorinated ligands and strategic modifications (e.g., proton bridging) significantly enhance catalytic performance.
- These findings contribute to the development of efficient iron-based electrocatalysts for hydrogen production.
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