Ruthenium Assemblies for CO₂ Reduction and H₂ Generation: Time Resolved Infrared Spectroscopy,...

Area of Science:

• Supramolecular Chemistry
• Photocatalysis
• Materials Science

Background:

• Development of efficient catalysts for sustainable energy applications like CO2 reduction and H2 evolution is crucial.
• Metal complexes offer tunable properties for photocatalytic applications.

Purpose of the Study:

• Synthesize and characterize two novel supramolecular complexes, RuRe and RuPt, for photocatalytic applications.
• Investigate the catalytic activity of these complexes for CO2 reduction and H2 evolution.
• Evaluate the influence of the catalytic metal and immobilization on a NiO semiconductor.

Main Methods:

• Synthesis of supramolecular complexes RuRe and RuPt.
• Photocatalytic activity testing in solution and on NiO.
• Spectroelectrochemistry (UV-Vis, IR) and time-resolved IR spectroscopy to study excited states and intermediates.
• Photoelectrochemical (PEC) cell studies.

Main Results:

• RuPt complex effectively generated hydrogen in solution and when immobilized on NiO.
• RuRe complex was inactive for CO2 reduction in solution.
• RuRe showed only trace CO production when immobilized on NiO under CO2 saturation.
• Ethyl-ester moieties reduced LUMO energies, localizing the excited state on peripheral ligands.

Conclusions:

• The RuPt complex is a promising catalyst for photocatalytic hydrogen evolution.
• The RuRe complex demonstrates limited efficacy for CO2 reduction under the tested conditions.
• Immobilization on NiO and the nature of the catalytic metal significantly influence photocatalytic performance.