DFT insights into electrocatalytic CO2 reduction to methanol on α-Fe2O3(0001) surfaces

Abstract

Electrocatalytic reduction of CO₂ to manufacture fuels and other useful chemicals is one of the appealing methods to reuse CO₂. Herein, electrocatalytic CO₂ reduction on a model α-Fe₂O₃(0001) surface catalyst has been investigated by means of density functional theory. This systematic study, involving 20 reaction intermediates and 63 distinct elementary reaction steps, has allowed the identification of a novel mechanism for the decomposition of the key intermediate *COOH. Methanol is the preferred product, with an overpotential of 0.8 V, over carbon monoxide (CO), formic acid (HCOOH), and formaldehyde (CH₂O). Formaldehyde formed on the surface will be converted into methanol. This work demonstrates the need for a complete investigation of possible pathways to find the most favourable one, beyond chemical intuition. Moreover, it suggests that hematite could be an interesting material for CO₂ reduction.