Copper foam supported g-C3N4-metal–organic framework bacteria biohybrid cathode catalyst for CO2 reduction in microbial electrosynthesis

Abstract

Abstract Microbial electrosynthesis (MES) presents a versatile approach for efficiently converting carbon dioxide (CO 2 ) into valuable products. However, poor electron uptake by the microorganisms from the cathode severely limits the performance of MES. In this study, a graphitic carbon nitride ( g- C 3 N 4 )-metal–organic framework (MOF) i.e. HKUST-1 composite was newly designed and synthesized as the cathode catalyst for MES operations. The physiochemical analysis such as X-ray diffraction, scanning electron microscopy (SEM), and X-ray fluorescence spectroscopy showed the successful synthesis of g- C 3 N 4 -HKUST-1, whereas electrochemical assessments revealed its enhanced kinetics for redox reactions. The g- C 3 N 4 -HKUST-1 composite displayed excellent biocompatibility to develop electroactive biohybrid catalyst for CO 2 reduction. The MES with g- C 3 N 4 -HKUST-1 biohybrid demonstrated an excellent current uptake of 1.7 mA/cm 2 , which was noted higher as compared to the MES using g- C 3 N 4 biohybrid (1.1 mA/cm 2 ). Both the MESs could convert CO 2 into acetic and isobutyric acid with a significantly higher yield of 0.46 g/L.d and 0.14 g/L.d respectively in MES with g- C 3 N 4 -HKUST-1 biohybrid and 0.27 g/L.d and 0.06 g/L.d, respectively in MES with g- C 3 N 4 biohybrid. The findings of this study suggest that g- C 3 N 4 -HKUST-1 is a highly efficient catalytic material for biocathodes in MESs to significantly enhance the CO 2 conversion.

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Identifiers

DOI

10.1038/s41598-023-49246-3

Journal

Scientific Reports

Year

2023