Catalytic Dehydrogenation of Formic Acid Promoted by Triphos-Co Complexes: Two Competing Pathways for H2 Production
Chou-Pen Tsai1, Chih-Yao Chen1, Yi-Lin Lin1
1Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
Inorganic Chemistry
|January 13, 2024
Summary
This study reports new cobalt complexes for efficient hydrogen production from formic acid. These catalysts achieve high turnover numbers and frequencies, offering a promising avenue for sustainable energy solutions.
Area of Science:
- Coordination Chemistry
- Catalysis
- Sustainable Energy
Background:
- Formic acid is a promising hydrogen storage molecule.
- Efficient catalytic systems are needed for formic acid dehydrogenation.
- Cobalt complexes offer potential as earth-abundant catalysts.
Purpose of the Study:
- Synthesize and characterize novel triphos-cobalt complexes.
- Investigate their catalytic activity for formic acid dehydrogenation.
- Elucidate the reaction mechanism and identify key intermediates.
Main Methods:
- Synthesis and structural characterization of triphos-Co(II) and triphos-Co(I)-H complexes.
- Experimental determination of activation energy barriers and kinetic isotope effects (KIE).
- Density functional theory (DFT) calculations, 1H NMR, and GC-MS analysis.
Main Results:
- Successful synthesis of [(κ3-triphos)CoII(CH3CN)2]2+ (1) and [(κ2-triphos)HCoI(CO)2] (4).
- Catalyst 1 achieved a maximum turnover number (TON) of ~1735 and turnover frequency (TOF) of ~483 h-1.
- KIE studies suggest H-COOH bond cleavage is rate-determining; DFT reveals two competing H2 production pathways.
Conclusions:
- Triphos-cobalt complexes are effective catalysts for formic acid dehydrogenation.
- The catalytic process involves distinct mechanistic pathways.
- This work provides insights into developing efficient catalysts for hydrogen generation.
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