Effect of sp2 species in a boron-doped diamond electrode on the electrochemical reduction of CO2

Abstract

The effect of sp2 carbon within a boron-doped diamond (BDD) electrode on the electrochemical reduction of CO2 is investigated for the first time. With increasing sp2 content, the Faradaic efficiency for the production of hydrogen (H2) under constant current density increases while that for the production of formic acid (HCOOH) decreases. Moreover, favorable electrolysis conditions for producing HCOOH shift in the negative potential direction with increasing sp2 content. This phenomenon is ascribed to the presence of adsorption sites on the sp2 carbon. This work provides guidance for selectively controlling the reduction of CO2 by adjusting the distribution of carbonaceous species in the BDD electrode.

Keywords

• Boron-doped diamond
• sp2 carbon
• CO2 reduction