UC Berkeley

Bioelectrochemical CO2-reducing rate at high potential was limited by poor bacteria-nanowire interface resulting from an inhospitable alkaline local environment. Tuning the bulk electrolyte pH and increasing its buffering capacity mitigated this issue and supported the formation of a close-packed nanowire-bacteria cathode. The resulting close-packed biohybrid operated with a CO2-reducing current density of 0.65 ± 0.11 mA cm−2 at ∼−1.2 V versus standard hydrogen electrode and enabled solar-powered CO2 fixation with solar-to-acetate efficiency of ∼3.6% over 1 week.