Additive-Free Formic Acid Dehydrogenation Catalyzed by a Cp*Ir Complex with Pyridyl-Pyrazole Ligand: Long-Term...

Area of Science:

• Catalysis and Materials Science
• Renewable Energy Technologies
• Green Chemistry

Background:

• Formic acid (FA) is a promising hydrogen carrier for renewable energy.
• Catalyst durability is a key challenge in FA dehydrogenation.
• Existing research often prioritizes activity over long-term stability.

Purpose of the Study:

• To design and develop a novel catalyst with enhanced durability for FA dehydrogenation.
• To investigate the long-term stability and performance of the catalyst.
• To understand the impact of impurities on the catalytic process.

Main Methods:

• Synthesis of iridium complexes with pyridyl-pyrazole ligands featuring electron-donating substituents.
• Testing catalyst performance under reflux conditions for FA dehydrogenation (HCOOH → H₂ + CO₂).
• Assessing catalyst durability through extended reaction times and continuous formic acid supply.
• Evaluating the effect of impurities, such as NaCl, on catalytic activity.

Main Results:

• A novel Ir-pyridyl-pyrazole complex demonstrated high activity and excellent durability without degradation.
• The catalyst sustained hydrogen generation over 43 days, producing 3.3 m³ of gas.
• NaCl was identified as a significant inhibitor of the catalytic reaction.
• The catalyst design strategy offers insights into improving catalyst longevity.

Conclusions:

• The developed iridium catalyst offers a robust solution for efficient and stable hydrogen generation from formic acid.
• This work highlights the importance of catalyst design for durability in practical applications.
• Further research should consider impurity effects for real-world implementation of FA-based hydrogen production.