Titania/reduced graphene oxide composite nanofibers for the direct extraction of photosynthetic electrons from microalgae for biophotovoltaic cell applications

Titanium oxide (TiO₂)/reduced graphene oxide (rGO) composite nanofibers were synthesized via an electrospinning technique and its potential electrochemical activity constructed its realization as an efficient anode catalyst in biophotovoltaic cells (BPV) with Chlorella vulgaris. The uniform adherence of GO sheets over the hydrolyzed Ti⁴⁺ ions, followed by its simultaneous reduction and crystallization, yielded the TiO₂/rGO composite nanofibers. The strong interconnection among the nanofibers and the intimate contact between rGO and TiO₂ in TiO₂/rGO composite improved the efficient electron transportation paths, facilitating the higher oxidation and continuous and stable currents as substantiated, respectively, from the cyclic voltammetry and chronoamperometry studies. By coupling the continuous electron conduction paths, proficient cell interaction, and elevated structural and chemical stabilities, TiO₂/rGO demonstrated the BPV power density of 34.66 ± 1.3 mW m⁻² with excellent durability, outperforming the BPV performances of previous reports. Thus the fundamental understanding achieved on the influences of nanocatalytic system in green energy generation opens up the new horizon of anticipation towards the development of sustainable and high-performance BPVs.