Hydrogenase Enzyme like Nanocatalysts FeS2 and FeSe2 for Molecular Hydrogen Evolution Reaction

We present a critical analysis of the mechanism of reversible hydrogen evolution reaction based on thermodynamics of hydrogen processes considering atomic and ionic species as intermediates. Clear distinction between molecular hydrogen evolution/oxidation (H$_2$ER and H$_2$OR) and atomic hydrogen evolution/oxidation (HER and HOR) reactions is made. It is suggested that the main reaction describing reversible H$_2$ER and H$_2$OR in acidic and basic solutions is: $\ce{H3O^+} + 2e^- \xrightleftharpoons{\mathrm{({H}_{2}^{+}})_{ad}} \ce{H2} + \ce{OH^-}$, which proceeds via the formation of hydrogen molecular ion as intermediate and its potential is $E^{0}$ = 0.414~V (at the standard Hydrogen electrode SHE scale). We analyse experimentally reported data with models which provide \emph{quantitative} match (R.J.Kriek et al., Electrochem. Sci. Adv. e2100041 (2021)). The experimentally observed slope of $\lg(Current)$ vs. $Potential$ equal to $\approx 30$~mV/dec corroborates the presented model of H$_2$ER/H$_2$ER based on \ce{H2$^+$} as intermediate.

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Cobalt Metal Organic Framework (Co-MOF) derived CoSe2/C hybrid nanostructures for Electrochemical Hydrogen Evolution Reaction Supported by DFT Studies

New Journal of Chemistry ◽

10.1039/d1nj05528c ◽

2022 ◽

Author(s):

Jogendra Nath Behera ◽

Rajat Kumar Tripathy ◽

Aneeya K Samantara ◽

Pratap Mane ◽

Brahmananda Chakraborty

Keyword(s):

Hydrogen Evolution ◽

Water Splitting ◽

Hydrogen Evolution Reaction ◽

Molecular Hydrogen ◽

Metal Organic Framework ◽

Hybrid Nanostructures ◽

Cobalt Metal ◽

Dft Studies ◽

Metal Organic ◽

Electrochemical Water Splitting

Generation of molecular hydrogen by electrochemical water splitting is a promising approach and its efficiency strictly adhere on the electrocatalyst used. Therefore, it’s an ongoing challenge to design materials having...

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A crystalline–amorphous Ni–Ni(OH)2 core–shell catalyst for the alkaline hydrogen evolution reaction

Journal of Materials Chemistry A ◽

10.1039/d0ta08735a ◽

2020 ◽

Vol 8 (44) ◽

pp. 23323-23329

Author(s):

Jing Hu ◽

Siwei Li ◽

Yuzhi Li ◽

Jing Wang ◽

Yunchen Du ◽

...

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Electrocatalytic Activity ◽

Core Shell ◽

Alkaline Conditions

Crystalline–amorphous Ni–Ni(OH)2 core–shell assembled nanosheets exhibit outstanding electrocatalytic activity and stability for hydrogen evolution under alkaline conditions.

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Cobaloxime-Based Double Complex Salts as Efficient and Versatile Catalysts for the Light-Driven Hydrogen Evolution Reaction

10.26434/chemrxiv.11537661 ◽

2020 ◽

Author(s):

Elisabeth Hofmeister ◽

Jisoo Woo ◽

Tobias Ullrich ◽

Lydia Petermann ◽

Kevin Hanus ◽

...

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Systematic Study ◽

Cobalt Complexes ◽

Spectroscopic Studies ◽

Double Complex ◽

Double Complex Salts ◽

Noble Metal Catalysts ◽

Reduction Potentials ◽

Complex Salts

Cobaloximes and their BF2-bridged analogues have emerged as promising non-noble metal catalysts for the photocatalytic hydrogen evolution reaction (HER). Herein we report the serendipitous discovery that double complex salts such as [Co(dmgh)2py2]+[Co(dmgBPh2)2Cl2]- can be obtained in good yields by treatment of commercially available [Co(dmgh)2pyCl] with triarylboranes. A systematic study on the use of such double complex salts and their single salts with simple counterions as photocatalysts revealed HER activities comparable or superior to existing cobaloxime catalysts and suggests ample opportunities for this compound class in catalyst/photosensitizer dyads and immobilized architectures. Preliminary electrochemical and spectroscopic studies indicate that one key advantage of these charged cobalt complexes is that the reduction potentials as well as the electrostatic interaction with charged photosensitizers can be tuned.

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2,2’-Dipyridylamine as Organic Molecular Electrocatalyst for Hydrogen Evolution Reaction in Acidic Electrolytes

10.26434/chemrxiv.8273627.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Xi Yin ◽

Ling Lin ◽

Hoon T. Chung ◽

Ulises Martinez ◽

Andrew M. Baker ◽

...

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Density Functional ◽

Low Cost ◽

Membrane Electrode Assembly ◽

Carbon Surface ◽

Membrane Electrode ◽

Durability Test ◽

Onset Potential ◽

Precious Metal Catalysts

Finding a low-cost and stable electrocatalyst for hydrogen evolution reaction (HER) as a replacement for scarce and expensive precious metal catalysts has attracted significant interest from chemical and materials research communities. Here, we demonstrate an organic catalyst based on 2,2’-dipyridylamine (dpa) molecules adsorbed on carbon surface, which shows remarkable hydrogen evolution activity and performance durability in strongly acidic polymer electrolytes without involving any metal. The HER onset potential at dpa adsorbed on carbon has been found to be less than 50 mV in sulfuric acid and in a Nafion-based membrane electrode assembly (MEA). At the same time, this catalyst has shown no performance loss in a 60-hour durability test. The HER reaction mechanisms and the low onset overpotential in this system are revealed based on electrochemical study. Density functional theory (DFT) calculations suggest that the pyridyl-N functions as the active site for H adsorption with a free energy of -0.13 eV, in agreement with the unusually low onset overpotential for an organic molecular catalyst.

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2,2’-Dipyridylamine as Organic Molecular Electrocatalyst for Hydrogen Evolution Reaction in Acidic Electrolytes

10.26434/chemrxiv.8273627 ◽

2019 ◽

Author(s):

Xi Yin ◽

Ling Lin ◽

Hoon T. Chung ◽

Ulises Martinez ◽

Andrew M. Baker ◽

...

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Density Functional ◽

Low Cost ◽

Membrane Electrode Assembly ◽

Carbon Surface ◽

Membrane Electrode ◽

Durability Test ◽

Onset Potential ◽

Precious Metal Catalysts

Finding a low-cost and stable electrocatalyst for hydrogen evolution reaction (HER) as a replacement for scarce and expensive precious metal catalysts has attracted significant interest from chemical and materials research communities. Here, we demonstrate an organic catalyst based on 2,2’-dipyridylamine (dpa) molecules adsorbed on carbon surface, which shows remarkable hydrogen evolution activity and performance durability in strongly acidic polymer electrolytes without involving any metal. The HER onset potential at dpa adsorbed on carbon has been found to be less than 50 mV in sulfuric acid and in a Nafion-based membrane electrode assembly (MEA). At the same time, this catalyst has shown no performance loss in a 60-hour durability test. The HER reaction mechanisms and the low onset overpotential in this system are revealed based on electrochemical study. Density functional theory (DFT) calculations suggest that the pyridyl-N functions as the active site for H adsorption with a free energy of -0.13 eV, in agreement with the unusually low onset overpotential for an organic molecular catalyst.

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