Bioadaptive Ni single atoms unlock high rate microbial electrosynthesis of isopropanol from CO₂.

Abstract

Hybrid systems that integrate electrochemical CO₂ reduction with microbial upgrading offer a viable route to high value organic compounds from CO₂ at ambient conditions. However, electrocatalyst deactivation in microbial growth media remains a key barrier, limiting efficiency and increasing cost. Here we show that a bioadaptive single-atom nickel catalyst (Ni SAC), coupled with genetically engineered Clostridium ljungdahlii, enables robust electrosynthesis of isopropanol (IPA) from CO₂ via a CO-mediated pathway. Instead of relying on H₂ as an electron carrier, the system applies high-rate CO formation in complex growth media, maintaining a tunable CO Faradaic efficiency up to 92%, which is 9.4 to 52.7 times greater than conventional Ag catalysts. This performance supports stable IPA production at current density of 10.8 A/m² and production rate of 161.3 mg/L/day. In situ Raman and X-ray absorption spectroscopy, together with theoretical calculations, indicate that the Ni SAC can resist competing organic adsorption and retain its coordination structure during CO₂ reduction in bioelectrolytes, providing a mechanistic basis for the catalyst stability and integrated process performance.