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Interfacial Charge Transfer Pathways in Photoelectrochemical H2 Evolution by a Single-Component Molecular Catalyst on
Eamon F Reynolds1, Dean M Bass1, Quentin R Loague1
1Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States.
Journal of the American Chemical Society
|July 13, 2026
Summary
This study introduces a novel photoactive catalyst for efficient hydrogen fuel production from water. This catalyst integrates light absorption and fuel generation, simplifying photoelectrosynthesis and advancing sustainable energy solutions.
Area of Science:
- Materials Science
- Electrochemistry
- Photocatalysis
Background:
- Dye-sensitized photoelectrosynthesis cells traditionally require separate photosensitizers and catalysts.
- Developing integrated photoactive catalysts is crucial for efficient solar fuel production.
Purpose of the Study:
- To develop and characterize a single-site photoactive catalyst for photoelectrochemical hydrogen evolution.
- To investigate the mechanism and efficiency of hydrogen evolution using this integrated catalyst.
Main Methods:
- Anchoring a photoactive iridium complex ([Cp*Ir(4,4'-Y2-bpy)Cl][Cl]) onto a mesoporous tin-doped indium oxide (ITO) electrode.
- Employing spectroelectrochemistry, cyclic voltammetry, and chronoamperometry to study reaction mechanisms.
- Utilizing Marcus theory and quantum yield measurements to analyze electron transfer pathways.
Main Results:
- The integrated catalyst efficiently produces hydrogen from water without external photosensitizers or sacrificial reductants.
- Spectroelectrochemistry revealed a single-site hydrogen evolution mechanism involving charge injection to ITO.
- Marcus theory analysis provided insights into competing interfacial electron transfer pathways.
Conclusions:
- The developed photoactive catalyst demonstrates high Faradaic efficiency and current densities for light-driven H2 evolution.
- Understanding interfacial electron transfer pathways is key to designing efficient hybrid molecular photoelectrocatalysts.
- This work establishes design principles for next-generation photocatalytic systems.
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