Developing micro-kinetic model for electrocatalytic reduction of carbon dioxide on copper electrode

A micro-kinetic model combining electrochemical rate theory and first-principles simulation is devel-oped to study the influences of solution pH and electrode potential on reaction rate, reaction pathways, and product distribution of electrocatalytic CO2 conversion. Two critical issues involved in electrochem-ical reaction mechanism are investigated: 1) competing concerted and sequential proton-electron trans-fer pathways, 2) competing thermodynamics-controlled and kinetics-controlled pathways. Our results show that the electrochemical reduction of CO2 to CO and HCOOH adopts a thermodynamics-controlled CPET mechanism at low pH, while follows a kinetics-controlled SPET mechanism at high pH. The electrocatalytic activity and selectivity can be effectively modulated by manipulating of solution pH and electrode potential. It is demonstrated that HCOOH is the main product at low overpotential while CO becomes the main product at high overpotential. In addition, increasing pH is conducive to improving the Faradic efficiency of HCOOH production and suppressing the hydrogen evolution reaction. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

A micro-kinetic model was developed to study the influences of solution pH and electrode potential on the reaction rate, pathways, and product distribution of electrocatalytic CO2 conversion. The study investigated competing proton-electron transfer pathways and pathways controlled by thermodynamics and kinetics, showing that different mechanisms occur at different pH levels and electrode potentials. Manipulating solution pH and electrode potential can effectively modulate the electrocatalytic activity and selectivity.