Analysis of cuprous oxide as a possible photocatalyst for carbon dioxide reduction

CO₂ reduction can be accomplished by photocatalysis, where the photocatalytic material uses absorbed solar energy to catalyze a CO₂ reduction reaction, forming products useful either directly as fuels or in the synthesis of fuels. Cu₂O is a semiconductor with a band gap of ∼2.0 V that has some demonstrated photocatalytic activity for water splitting and whose electronic and optical properties show promise for use in CO₂ reduction. Using hybrid density functional theory (DFT) to calculate its work function and the GW approximation to calculate its band gap, we can reproduce measurements and furthermore show that its conduction band edge potential is positioned favorably for CO₂ reduction. DFT+U theory is being used to model the reaction of H₂O and CO₂ on Cu₂O surfaces. Embedded correlated wavefunction methods are used for further refinement in a localized picture of excited states and surface reactions.