Facile preparation of tetrafluoro-substituted cobalt phthalocyanine nanorods attached on carbon nanotubes for efficient electrocatalytic CO2 reduction

A tetrafluoro substituted CoPc (CoF4Pc), which is well dispersed in N,N-dimethylformamide (DMF), was used to modify carbon nanotubes (CNTs) via a facile sonication method, resulting in CoF4Pc nanorods with the length lower than 30 nm on the CNT surface. The as-fabricated CoF4Pc-CNT composites showed superior CO2RR catalytic activity compared with that of individual CoF4Pc, due to enhanced mass transfer and electrical conductivity arising from the CNT substrate. The CoF4Pc-CNT composite with the CoF4Pc/CNT weight ratio of 2:30 exhibited the highest CO current density of 29.0 mA cm(-2) and CO selectivity of 91.8% at - 0.85 V vs. reversible hydrogen electrode (RHE) in a flow cell setup containing 0.5 M KHCO3, which was ascribed to enhanced charge transfer induced by highly dispersion of CoF4Pc nanorods, and good conductivity of CNT substrates. The work provides new insights for developing low-cost, effective, phthalocyanine-based catalysts for electrochemical CO2RR.