Confining a Single Water Molecule Through Molecular Crystal Engineering for Water Oxidation.

Area of Science:

• Materials Science
• Catalysis
• Physical Chemistry

Background:

• Hydrogen-bonded water clusters hinder the study of isolated water molecule reactivity.
• Understanding monomeric water catalysis is crucial for aqueous-phase chemistry.

Purpose of the Study:

• To investigate the catalytic behavior of isolated water molecules.
• To design a platform for studying monomeric water in a controlled environment.

Main Methods:

• Fabrication of a molecular crystal (CB-H2O) confining single water molecules in tetrahedral cavities.
• Photocatalytic testing of CB-H2O for water-to-hydrogen peroxide conversion.
• Verification using isotopic labeling and in-situ spectroscopy.
• Theoretical calculations to understand reaction mechanisms.

Main Results:

• CB-H2O demonstrated high photocatalytic activity for water-to-hydrogen peroxide conversion (7.03 mmol g⁻¹ h⁻¹).
• Achieved an 11.6-fold enhancement compared to controls lacking cavities.
• Confinement of monomeric water significantly lowered the activation barrier for water oxidation.

Conclusions:

• Monomeric water catalysis is an efficient and distinct paradigm.
• Molecular crystal engineering is a viable strategy for tailoring water-involved reactions.
• This approach offers a new pathway for sustainable catalysis.