Highly ordered mesoporous carbon/iron porphyrin nanoreactor for the electrochemical reduction of CO2

Abstract

A variety of carbon materials such as carbon nanotubes and graphene have been widely investigated as conductive substrates to immobilize metal complex-based catalysts for electrocatalytic CO₂ reduction. However, highly ordered mesoporous carbons have received scant attention as substrates for CO₂ reduction electrocatalysts. The unique porous structure of such carbon provides the opportunity to not only house catalytically active materials but also facilitate reactant transport. In this work, we propose a simple approach for immobilization of the highly active and cost-efficient molecular catalyst iron porphyrin, into a highly ordered mesoporous carbon, CMK-3 having a large surface area of 1345 m² g⁻¹via a simple vacuum infiltration method. The resulting heterogeneous electrocatalyst (CMK-FeTPP) is utilized for the conversion of aqueous CO₂ into CO with 92.1% faradaic efficiency and a high effective turnover frequency of 3.9 s⁻¹ at an overpotential of 680 mV. We believe that this new approach has the potential to be widely used to fabricate efficient electrocatalysts for not only CO₂ conversion but also other electrochemical gas conversion systems.