Formic acid stability in different solvents by DFT calculations.

Area of Science:

• Green energy technologies
• Sustainable chemical processes
• Hydrogen storage solutions

Background:

• Developing sustainable energy solutions is crucial.
• Formic acid (FA) production via CO2 hydrogenation offers a pathway for hydrogen storage.
• FA adduct stabilization is solvent and condition-dependent.

Purpose of the Study:

• To investigate the thermodynamic stability of FA adducts in various solvents.
• To understand the influence of solvent dielectric permittivity and temperature on FA stabilization.
• To identify optimal conditions for enhanced hydrogen storage in CO2 conversion.

Main Methods:

• Density Functional Theory (DFT) calculations using Quantum ESPRESSO.
• vdW-DF functional with van der Waals (vdW) forces and PAW method.
• Self-Consistent Continuum Solvation (SCCS) approach for electrostatic solvation.

Main Results:

• A wide range of dielectric permittivity values, particularly in DMSO and water, stabilize FA.
• FA complex formation with water is temperature-dependent and more influential than with amines in aqueous solvents.
• Thermodynamic stability of FA is favored in non-organic solvents with dielectric permittivity closer to water.

Conclusions:

• Aqueous solvent mixtures, potentially with ionic components, can enhance thermodynamic stability for hydrogen storage.
• Optimizing solvent properties is key for efficient CO2 conversion and H2 storage.
• Findings support the development of advanced green energy technologies.