Fig. 4: Mechanistic insight from quantum mechanics calculations.
From: Strain enhances the activity of molecular electrocatalysts via carbon nanotube supports
a,b, Absorption energy versus potential (URHE, V) (a) and n − n0 (b), where n is the number of electrons added (n − n0 = 1 indicates 1 electron has been added to the neutral system). c, Free energies of curved and flat CoPcH4 with and without CO adsorption versus n − n0. d, Representative N–Co–N angle and Co–C and C–O distances of CoPcH4. e, N–Co–N angle (degrees) versus n − n0 for the curved and flat structures. f, Co–C and C–O distances (Å) versus n − n0. g, Free energies (eV) at U = −0.93 V versus RHE and pH 7 for CO2 reduction to methanol on curved and flat CoPc. ΔGC and ΔGF are reaction step free energies for the curved and flat CoPc, respectively. For flat CoPc it is favourable for CO to desorb so it is not available for subsequent steps toward methanol. For curved CoPc, it is not favourable to desorb CO, making it available for production of methanol. Green boxes indicate the preferred intermediates and red boxes indicate the higher-energy intermediates.
