Metal-Free Fluorine-Doped Carbon Electrocatalyst for CO2 Reduction Outcompeting Hydrogen Evolution

The electrochemical CO2 reduction (ECDRR), as a key reaction in artificial photosynthesis to implement renewable energy conversion/storage, has been inhibited by the low efficiency and high costs of the electrocatalysts. Herein, we synthesize a fluorine-doped carbon (FC) catalyst by pyrolyzing commercial BP2000 with a fluorine source, enabling a highly selective CO2-to-CO conversion with a maximum Faradaic efficiency of 90% at a low overpotential of 510mV and a small Tafel slope of 81mVdec(-1), outcompeting current metal-free catalysts. Moreover, the higher partial current density of CO and lower partial current density of H-2 on FC relative to pristine carbon suggest an enhanced inherent activity towards ECDRR as well as a suppressed hydrogen evolution by fluorine doping. Fluorine doping activates the neighbor carbon atoms and facilitates the stabilization of the key intermediate COOH* on the fluorine-doped carbon material, which are also blocked for competing hydrogen evolution, resulting in superior CO2-to-CO conversion.