(Invited) Non-Precious Metal Catalysts with Designed Carbon Nanostructures and Controlled Active Sites for Oxygen Reduction Reaction and CO2 Reduction

Abstract

To replace scarce and expensive Pt-based oxygen reduction reaction (ORR) catalysts in acidic conditions, non-precious metal catalysts (NPMCs) based on third-row transition metals and N-doped carbon (M/N/C) have been intensively studied to date. Here, we present a novel versatile strategy to control and enhance the activity of the single Fe-N 4 site by incorporating electron-withdrawing/donating functionalities on the carbon plane. These incorporated functionalities change the strength of the electronic effect, which is derived from the delocalized pi-band of carbon plane to the d -orbital of the Fe ion in Fe-N 4 site; therefore, the adsorption strength of ORR intermediates at the Fe-N 4 site was controlled by incorporated functionalities. Electrochemical CO 2 reduction reaction (CO 2 RR) has attracted a lot of interest as a highly potential CO 2 utilization system. Due to the high overpotential in CO 2 RR, the development of an effective catalyst is highly required for CO 2 based long-term energy storage system. We present a metal-organic hybrid catalyst (Co-PPy-C), which consists of Co and polypyrrole, as a highly active electrocatalyst for CO 2 RR. Co-PPy-C exhibited high Faradaic efficiency and metal mass activity for CO production at low overpotential region.