Design of a novel photoelectrochemical enzymatic biofuel cell with high power output under visible light

Photoelectrochemical enzymatic biofuel cell (PEBFC) shows the obvious advantages in the renewable energy conversion field. However, because of the low utilization efficiency of solar energy and the unendurable power output, PEBFC cannot satisfy the demand of practical applications. Herein, a novel PEBFC prototype is designed. Taking a TiO₂ nanorod arrays (NRAs) decorated graphene–cadmium sulfide quantum dots (GR–CdS QDs) hybrid at fluorine-doped tin oxide (FTO) glass electrode as the photoanode, it can catalyze the oxidation of ascorbic acid (AA) effectively, with the oxidation current being as high as –137.8 μA cm⁻², and the anodic open circuit potential (E_a^OCP) reaching approximately –0.52 V; using a laccase–bound three–dimensional graphene–single walled carbon nanotubes (3D GR–SWCNTs–laccase) hybrid electrode as the biocathode, along with 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), the biocathode can catalyze the reduction of oxygen remarkably, and the cathodic open circuit potential (E_c^OCP) is as high as 0.54 V. Under optimal conditions, such PEBFC can obtain sufficient high open circuit voltage (V_oc) of 1.05 V and maximum power output density (P_max) of 227.5 μW cm⁻², respectively. Two PEBFCs connected in series can light a red light-emitting diode (LED) successfully.