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Reversibility and efficiency in electrocatalytic energy conversion and lessons from enzymes
Fraser A Armstrong1, Judy Hirst
1Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom. fraser.armstrong@chem.ox.ac.uk
Summary
Enzymes are highly efficient electrocatalysts, driving sluggish reactions like CO2 reduction with remarkable reversibility. Their evolved efficiency sets a high bar for future energy catalysts.
Area of Science:
- Biocatalysis
- Electrochemistry
- Energy Science
Background:
- Enzymes are known for high catalytic efficiency.
- Electrocatalysis often requires significant overpotential and suffers from sluggish reaction rates.
- Synthetic catalysts struggle with certain challenging redox reactions.
Purpose of the Study:
- To investigate the potential of enzymes as electrocatalysts.
- To demonstrate enzyme-catalyzed redox reactions at electrodes.
- To compare enzyme electrocatalytic performance with synthetic catalysts.
Main Methods:
- Immobilizing enzymes onto electrode surfaces.
- Performing electrochemical analysis, including voltammetry.
- Studying redox reactions, such as CO2 reduction.
Main Results:
- Enzymes exhibit high electrocatalytic activity, generating significant currents.
- Enzymatic electrocatalysis shows sharp, bidirectional voltammetric waves at equilibrium potentials.
- Enzymes render previously irreversible reactions, like CO2 reduction, electrochemically reversible.
Conclusions:
- Enzymes are exceptionally efficient electrocatalysts.
- Biological evolution has optimized enzymes for thermodynamic efficiency.
- Enzymes provide a benchmark for developing advanced energy catalysts.
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