A supported polymeric organic framework composed of dual electrocatalytically active sites for high-performance carbon dioxide electroreduction

Abstract

The electrocatalytic reduction of CO₂ to CO and other sustainable fuels presents an attractive approach for alleviating the energy crisis and environmental problems. Carbon nanotube (CNT) hybridization and the incorporation of dual catalytic sites into a polymeric organic framework (POF) are promising strategies for boosting the electrocatalytic performance of POF-tailored electrocatalysts. Herein, we demonstrate a combined nanoscale and molecular-level strategy to construct an organic–inorganic hybrid material by the template-directed in situ polymerization of ultrathin POF layers with isolated Co(II) porphyrin (Por-) and Co(II) bipyridine sites on the CNT scaffold. As an electrocatalyst for CO₂-to-CO conversion in an aqueous solution, the resultant POF@CNT shows higher electrocatalytic activity and selectivity compared to other comparative materials. Specifically, it exhibits the highest faradaic efficiency for CO production (FE_CO) of 97.5% at the overpotential of 600 mV, a superior turnover frequency (TOF) of 36.6 s⁻¹ at −1.0 V vs. the reversible hydrogen electrode (RHE), and remarkable long-term stability. These metrics are superior to or at least comparable to most of its organic or inorganic competitors. The remarkable catalytic performance of POF@CNT can be attributed to the combined effects of CNT hybridization and the dual active sites in the POF structure, which facilitates interfacial electron transfer and enables a high degree of catalytically active site exposure.