Understanding the Local Chemical Environment of Bioelectrocatalysis

This work applies electrochemical and computational techniques to explore the local environment of fuel-producing oxidoreductases within porous electrode architectures. This improved understanding of the local environment enabled simple manipulation of the electrolyte solution, by adjusting the bulk pH and buffer pKa, to achieve an optimum local pH for maximal activity of the immobilised enzyme. When applied to macroporous inverse opal electrodes, the benefits of higher loading and increased mass transport were employed and, consequently, the electrolyte adjusted to reach −8.0 mA cm−2 for the H2 evolution reaction (HER) and −3.6 mA cm−2 for the CO2 reduction reaction (CO2RR), demonstrating an 18-fold improvement on previously reported enzymatic CO2RR systems.