Manipulating Coordination-Unsaturated H-Bond toward Efficient Electrochemical Hydrogen Isotope Separation

Area of Science:

• Chemical Engineering
• Materials Science
• Nuclear Engineering

Background:

• Heavy water (D2O) is crucial for nuclear reactors and isotopic tracing.
• Current water electrolysis methods for D2O separation suffer from low efficiency due to similar O-H and O-D bond dissociation energies (BDEs).

Purpose of the Study:

• To develop an advanced, energy-efficient method for separating hydrogen and deuterium (H/D) isotopes.
• To magnify the BDE discrepancy between O-H and O-D bonds for improved H/D separation.

Main Methods:

• Electrochemical water electrolysis utilizing organic additives with varying Gutmann donor numbers.
• Tuning the hydrogen-bond network through sulfolane (SUL) additive.
• Analysis of BDEs and H/D-bond network characteristics.

Main Results:

• The BDE difference between O-H and O-D bonds was amplified over sixfold (0.95 to 6.24 meV).
• Sulfolane additive induced a moderate H/D-bond network, enhancing separation.
• Achieved gas-liquid separation coefficients of 17.28 and 8.8% D atomic fraction enrichment.

Conclusions:

• Modulating the H/D-bond network via organic additives is an effective strategy for electrochemical H/D isotope separation.
• This approach offers a promising pathway for energy-efficient D2O production.