Fuel-Free Bio-photoelectrochemical Cells Based on a Water/Oxygen Circulation System with a Ni:FeOOH/BiVO4 Photoanode.

A bio-photoelectrochemical cell (BPEC) based on a fuel-free self-circulation water-oxygen-water system was fabricated. It consists of Ni:FeOOH modified n-type bismuth vanadate (BiVO4 ) photoanode and laccase catalyzed biocathode. In this BPEC, irradiation of the photoanode generates photocurrent for photo-oxidation of water to oxygen, which is reduced to water again at the laccase biocathode. Of note, the by-products of two electrode reactions could continue to be reacted, which means the H2 O and O2 molecules are retained in an infinite loop of water-oxygen-water without any sacrificial chemical components. As a result, the assembled fuel-free BPEC exhibits good performance with an open-circuit potential of 0.97 V and a maximum power density of 205 μW cm-2 at 0.44 V. This BPEC based on a self-circulation system offers a fuel-free model to enhance multiple energy conversion and application in reality.