Fig. 3.

The role of the ionic liquid in Au NP-photocatalyzed CO₂RR. a,b DFT-optimized geometries of [EMIM*-CO₂] (a) and [H₂O-CO₂] (b) complexes. C, H, O, and N atoms are depicted by gray, white, red, and blue spheres, respectively. Key bond lengths, bond angles, and the energy of intermolecular interaction, E_m-m, are indicated for each of the complexes. c–e DFT-computed free energy cost, ∆G, of formation of the 1e⁻ adduct of CO₂ (c), 1e⁻ adduct of [EMIM*-CO₂] (d), and 1e⁻ adduct of CO₂ in the presence of EMIM⁺ (e). In the latter case, the 1e⁻ adduct of CO₂, CO₂^•−, is stabilized by complexation with EMIM⁺ as described by the net process: EMIM⁺ + CO₂ + e⁻→ [EMIM-CO₂]^•. In c–e, the free energy of each species is indicated in parentheses. Scale bars are 1 eV in length