Electrodes modified with iron porphyrin and carbon nanotubes: application to CO2 reduction and mechanism of synergistic electrocatalysis

Electrodes modified with iron porphyrin and carbon nanotubes (FeP-CNTs) were prepared and used for CO2 electroreduction. The adsorption of iron porphyrin onto the multiwalled carbon nanotubes was characterized by scanning electron microscopy and ultraviolet and visible spectroscopy. The electrochemical properties of the modified electrodes for CO2 reduction were investigated by cyclic voltammetry and CO2 electrolysis. The FeP-CNT electrodes exhibited less negative cathode potential and higher reaction rate than the electrodes modified only with iron porphyrin or carbon nanotubes. A mechanism of the synergistic catalysis was proposed and studied by electrochemical impedance spectroscopy and electron paramagnetic resonance. The direct electron transfer between iron porphyrin and carbon nanotubes was examined. The current study shed light on the mechanism of synergistic catalysis between CNTs and metalloporphyrin, and the iron porphyrin-CNT-modified electrodes showed great potential in the efficient CO2 electroreduction.ElectrochemistrySCI(E)EI7ARTICLE6,SI1657-16641