Joule
ReportClose-Packed Nanowire-Bacteria Hybrids for Efficient Solar-Driven CO2 Fixation
Context & Scale
Bioinorganic interface is a key determinant for microbial catalytic CO2 fixation. However, the correlation between bioinorganic interface and CO2-conversion efficiency has not been systematically studied as a function of operational parameters. Here, investigation of the microorganism-cathode interface allowed us to boost the CO2-reducing rate in a silicon nanowire/Sporomusa ovata system. We found that the 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 facilitated the formation of a close-packed nanowire-bacteria cathode. The resulting close-packed biohybrid achieved a CO2-reducing current density of 0.65 ± 0.11 mA cm−2. Our system enabled solar-powered CO2 fixation with solar-to-acetate efficiency of ∼3.6% over 1 week.