Enhancing long-term stability of bio-photoelectrochemical cell by defect engineering of a WO3-x photoanode

Abstract

Bio-photoelectrochemical cells (BPECs) can further expand the use of conventional biofuel cells for renewable energy, but the poor stability of the photoelectrode still hinders their practical application. Herein, a BPEC capable of long-term operating in a fuel-free model is fabricated by WO3-x photoanode with oxygen vacancy (Ov) and bilirubin oxidase catalyzed biocathode. The construction of Ov on the WO3 surface significantly suppresses the dissolution of W species into the electrolyte, and improves the charge separation efficiency and the reaction kinetics during the photoelectrochemical oxygen evolution process, thus enhancing the stability and power output performance of the BPEC. As a result, the assembled BPEC can output an open circuit voltage of 0.81 V and deliver a maximum output power of up to 283 μW cm−2. Impressively, the BPECs maintain 97% of their original power after 36000 s of consecutive discharge under an enclosed environment. This fuel-free BPEC based on a robust WO3-x photoanode shows excellent promise for accurate application.