Integrated Capture and Electroreduction of Low‐Concentration CO2 to CO Using Geopolymer|Graphene‐Cobalt Phthalocyanine Composite

Abstract

Green electricity‐driven electrocatalytic CO2 reduction (e‐CO2RR) has emerged as a promising approach to upcycle CO2 into valuable chemicals and fuels, paving the way for a carbon‐neutral economy. The success of such a device relies on the development of cost‐effective catalysts that can efficiently and selectively catalyze e‐CO2RR. In the present contribution, the high activity and selectivity of graphene‐supported CoPc (graphene‐CoPc) are demonstrated toward CO generation from e‐CO2RR by encapsulating graphene|CoPc into Perlite–Metakaolin‐based geopolymer (geopolymer|graphene‐CoPc). The high electric conductivity (3.52 ± 0.4 S m−1) and CO2 adsorption capability (0.16 mmol CO2 g−1) of the geopolymer matrix, obtained through the systematic investigation and optimization of synthetic conditions, facilitate the charge transfer and provide high local CO2 concentration. Consequently, this significantly enhancing both turnover frequency (2.3 ± 0.3 s−1) and Faradaic efficiency (93.7 ± 3.1%) of geopolymer|graphene‐CoPc for CO production from the low‐concentration CO2 (≈40%) in simulated biogas atmosphere at a low η of 0.69 V as compared to the pristine graphene‐CoPc (turnover frequency: 1.37 ± 0.1 s−1 and Faradic efficiency: 46.3 ± 2.0%).

Keywords

• biogas upgrading
• CO2 affinities
• diluted CO2
• electrochemical upcycling of CO2
• graphene‐supported cobalt phthalocyanine