Hydrogen Evolution via Oxygen Tolerant [NiFe]-Hydrogenase Immobilized on TiO2 Nanotubes

Abstract

[FeFe]-hydrogenase has been of great interest due to its high enzymatic activity for hydrogen evolution reactions (HERs). However, the big challenge of [FeFe]-hydrogenase is a significant performance degradation in aerobic conditions. On the other hand, [NiFe]-hydrogenase of E. coli has an oxygen tolerant property. Therefore, using [NiFe]-hydrogenase is an effective solution to avoid performance degradation in aerobic conditions. Herein, we extracted [NiFe]-hydrogenases from E. coli and immobilized them on the TiO2 nanotube (TNT) electrode prepared by pyrrole-based electropolymerization for application in aerobic conditions. As a result, we can confirm that [NiFe]-hydrogenases coated TNT electrode demonstrates the increased HER activity underaerobic condition than control samples in in-vitro activity test using methylene viologen and linear sweep voltammetry.