A solar-rechargeable bio-photoelectrochemical system based on carbon tracking strategy for enhancement of glucose electrometabolism

Establishing a green power system to achieve reasonable and high-efficiency renewable energy utilization is undoubtedly a large engine to promote the development of sustainable socio-economy. In this context, an ingenious carbon tracking strategy was proposed to enhance glucose electrometabolism by developing a solar-rechargeable bio-photoelectrochemical system (BPECS). The prototype of this BPECS is a glucose/O2 photo-biofuel cell (PBFC) that contains a Prussian blue/glucose oxidase (PB/GOD) biocathode and a Mo-doped bismuth vanadate (Mo:BiVO4) photoanode. Benefiting from the specific electrooxidation selectivity of Mo:BiVO4 towards gluconic acid, namely the by-product of biocathode, the carbon track from glucose (C6H12O6) to gluconic acid (C6H12O7) and then to arabinose (C5H10O5) can be achieved in one-chambered PBFC. Under light illumination, this PBFC obtained an open circuit voltage of 0.52 ± 0.01 V and a maximum output power density of 98.11 ± 2.26 μW cm−2. Furthermore, in response to the intermittent nature of sunlight, a polypyrrole (PPy) capacitor electrode, as energy storage module, was integrated into PBFC to assemble the solar-rechargeable BPECS. Through bio-discharge (biocathode-PPy) and photo-charge (PPy-photoanode) of BPECS, the carbon track is divided into two-step electrometabolism process, which effectively avoids the deficiency of traditional cascade kinetics. Meanwhile, consecutive electricity output can be obtained from BPECS whether day or night. Based on the proposed carbon tracking strategy, this developed solar-rechargeable BPECS not only enhances glucose electrometabolism, but also achieves reasonable utilization of sunlight, which provides a judicious research model for high-efficiency renewable energy exploitation.