Copper foam supported g-C3N4-metal–organic framework bacteria biohybrid cathode catalyst for CO2 reduction in microbial electrosynthesis
Md Tabish Noori, Mansi, Shashank Sundriyal, Vishal Shrivastav, Balendu Sekhar Giri, Marcin Hołdyński, Wojciech Nogala, Umesh Tiwari, Bhavana Gupta, Booki Min
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.