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A prolific catalyst for dehydrogenation of neat formic acid.

Celaje JJ, Lu Z, Kedzie EA, Terrile NJ, Lo JN, Williams TJ - Nat Commun (2016)

Bottom Line: While many catalysts exist for both formic acid dehydrogenation and carbon dioxide reduction, solutions to date on hydrogen gas release rely on volatile components that reduce the weight content of stored hydrogen and/or introduce fuel cell poisons.These are avoided here.The catalyst utilizes an interesting chemical mechanism, which is described on the basis of kinetic and synthetic experiments.

View Article: PubMed Central - PubMed

Affiliation: Donald P. and Katherine B. Loker Hydrocarbon Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, USA.

ABSTRACT
Formic acid is a promising energy carrier for on-demand hydrogen generation. Because the reverse reaction is also feasible, formic acid is a form of stored hydrogen. Here we present a robust, reusable iridium catalyst that enables hydrogen gas release from neat formic acid. This catalysis works under mild conditions in the presence of air, is highly selective and affords millions of turnovers. While many catalysts exist for both formic acid dehydrogenation and carbon dioxide reduction, solutions to date on hydrogen gas release rely on volatile components that reduce the weight content of stored hydrogen and/or introduce fuel cell poisons. These are avoided here. The catalyst utilizes an interesting chemical mechanism, which is described on the basis of kinetic and synthetic experiments.

No MeSH data available.


Related in: MedlinePlus

Synthesis and structure of catalyst precursor cation 1.Elipsoids are drawn at the 50% probability level.
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f1: Synthesis and structure of catalyst precursor cation 1.Elipsoids are drawn at the 50% probability level.

Mentions: Complex 1, which is easily prepared from known materials (Fig. 1), decomposes FA (500 μl, 12.7 mmol) with NaO2CH co-catalyst (5 mol%) at 50 p.p.m. loading and 90 °C, resulting in the production of 386 ml of gas (62% conversion; TON=12,530) after 13 h. The mass balance of FA condenses as a liquid in the reactor out of reach of the catalyst (vide infra). The rate of the reaction is constant through ca. 20% of conversion before it accelerates as FA disappears (Supplementary Fig. 1). At the end of the reaction, a pale orange solid (the catalyst system: an iridium complex and sodium formate) remains at the bottom of the reaction vessel. Recharging the reaction flask with FA and reheating to 90 °C results in continued H2 production without any catalyst regeneration.


A prolific catalyst for dehydrogenation of neat formic acid.

Celaje JJ, Lu Z, Kedzie EA, Terrile NJ, Lo JN, Williams TJ - Nat Commun (2016)

Synthesis and structure of catalyst precursor cation 1.Elipsoids are drawn at the 50% probability level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834634&req=5

f1: Synthesis and structure of catalyst precursor cation 1.Elipsoids are drawn at the 50% probability level.
Mentions: Complex 1, which is easily prepared from known materials (Fig. 1), decomposes FA (500 μl, 12.7 mmol) with NaO2CH co-catalyst (5 mol%) at 50 p.p.m. loading and 90 °C, resulting in the production of 386 ml of gas (62% conversion; TON=12,530) after 13 h. The mass balance of FA condenses as a liquid in the reactor out of reach of the catalyst (vide infra). The rate of the reaction is constant through ca. 20% of conversion before it accelerates as FA disappears (Supplementary Fig. 1). At the end of the reaction, a pale orange solid (the catalyst system: an iridium complex and sodium formate) remains at the bottom of the reaction vessel. Recharging the reaction flask with FA and reheating to 90 °C results in continued H2 production without any catalyst regeneration.

Bottom Line: While many catalysts exist for both formic acid dehydrogenation and carbon dioxide reduction, solutions to date on hydrogen gas release rely on volatile components that reduce the weight content of stored hydrogen and/or introduce fuel cell poisons.These are avoided here.The catalyst utilizes an interesting chemical mechanism, which is described on the basis of kinetic and synthetic experiments.

View Article: PubMed Central - PubMed

Affiliation: Donald P. and Katherine B. Loker Hydrocarbon Institute and Department of Chemistry, University of Southern California, Los Angeles, California 90089-1661, USA.

ABSTRACT
Formic acid is a promising energy carrier for on-demand hydrogen generation. Because the reverse reaction is also feasible, formic acid is a form of stored hydrogen. Here we present a robust, reusable iridium catalyst that enables hydrogen gas release from neat formic acid. This catalysis works under mild conditions in the presence of air, is highly selective and affords millions of turnovers. While many catalysts exist for both formic acid dehydrogenation and carbon dioxide reduction, solutions to date on hydrogen gas release rely on volatile components that reduce the weight content of stored hydrogen and/or introduce fuel cell poisons. These are avoided here. The catalyst utilizes an interesting chemical mechanism, which is described on the basis of kinetic and synthetic experiments.

No MeSH data available.


Related in: MedlinePlus