Toward Escherichia coli bacteria machine for water oxidation

Area of Science:

• Biocatalysis
• Materials Science
• Electrochemistry

Background:

• Nature utilizes manganese (Mn) oxide catalysts for water oxidation in photosynthetic organisms.
• Mn oxides are promising candidates for artificial water-oxidizing catalysts.

Purpose of the Study:

• To develop straightforward methods for synthesizing Escherichia coli bacteria/Mn oxide compounds.
• To investigate the water oxidation properties of these novel compounds.

Main Methods:

• Synthesis of bacteria/Mn oxide compounds using two distinct methods.
• Characterization using X-ray photoelectron spectroscopy, electron microscopy (SEM, HR-TEM), visible spectroscopy, DRIFTS, Raman, and XRD.
• Electrochemical analysis including linear sweep voltammetry.

Main Results:

• Successful formation of Escherichia coli bacteria/Mn oxide compounds, with one method preserving the bacterial template.
• Electrochemical studies revealed attributed redox potentials.
• Water oxidation onset potential for the bacteria/Mn oxide catalyst was 1.56 V vs. NHE, a decrease of ~120 mV compared to bacteria alone (1.68 V vs. NHE).

Conclusions:

• The synthesized Escherichia coli bacteria/Mn oxide compounds are effective water-oxidation catalysts.
• Incorporation of Mn oxide significantly lowers the overpotential for water oxidation.
• This work presents a promising bio-hybrid approach for developing efficient water-splitting catalysts.