Green synthesis of reduced graphene oxide by using tropical microalgae and its application in biophotovoltaic devices

The successful commercialization of algal biophotovoltaics (BPV) technology hinges upon a multifaceted approach, encompassing factors such as the development of a cost-efficient and highly conductive anode material. To address this issue, we developed an environmentally benign method of producing reduced graphene oxide (rGO), using concentrated Chlorella sp. UMACC 313 suspensions as the reducing agent. The produced rGO was subsequently coated on the carbon paper (rGO-CP) and used as the BPV device's anode. As a result, maximum power density was increased by 950% for Chlorella sp. UMACC 258 (0.210 mW m^-2) and 781% for Synechococcus sp. UMACC 371 (0.555 mW m^-2) compared to bare CP. The improved microalgae adhesion to the anode and improved electrical conductivity of rGO brought on by the effective removal of oxygen functional groups may be the causes of this. This study has demonstrated how microalgal-reduced GO may improve the efficiency of algal BPV for producing bioelectricity.