Sandwich-Type Enzymatic Fuel Cell Based on a New Electro-Conductive Material - Ion Jelly

In the present work, Ion Jelly films based on 1-ethyl-3-methylimidazolium ethylsulfate, with incorporated redox proteins and enzymes were deposited on carbon screen-printed electrodes (SPEs), and their electrochemical characterization was attained. Ion Jelly synthesis was carried out simultaneously with protein incorporation in its structure, followed by a maturation step under controlled atmosphere (4 days at 4 °C and water activity (aw) of 0.76). The electrochemical response of the material was characterized, and a sandwich-type fuel cell configuration was subsequently built, consisting of two SPEs containing two independent Ion Jelly discs in the middle; one disc incorporated Desulfovibrio gigas cytochrome c₃ and [NiFe]-hydrogenase, while the other disc contained aldehyde oxidoreductase, constituting the biocathode and bioanode of the cell, respectively. Cell voltage increased with time in the presence of benzaldehyde, in agreement with a successful electronic pathway across the cell and the concomitant aldehyde oxidoreductase enzymatic activity. In the cathodic side assays, hydrogenase showed catalytic activity towards H⁺ reduction to H₂.