Why Is There Such a Small Overpotential for O[sub 2] Electroreduction by Copper Laccase?

Four-electron reduction of O2 over multiple CuI centers: Quantum theory

“…A linear relationship between free and internal energies has also been demonstrated for Reactions (1)-(5) in acid and base solution, which supports the idea that the difference in solvation energies for reactants and products are nearly constant and small, of magnitude 0.5 eV, for reactions involving oxygen and water in solution [34,35]. In an earlier communication it was argued that the solvation stabilizations of the reactant and product for each step are reduced by nearly the same amount because the solvation cloud is reduced by nearly the same amount for the reactant and product and is replaced by the bond to the catalyst site [36]. Linear Gibbs energy relationships are common in chemistry.…”

“…In our model, the Cu I centers were in loose association, consistent with the flexible nature of the enzyme. Parts of the results and conclusions given here were introduced in a recent communication [36].…”

Graphyne nanotubes as electrocatalysts for oxygen reduction reaction: the effect of doping elements on the catalytic mechanisms

“…However, due to the fact that the OH species could be very stably adsorbed on the P-GNT surface (E ads of À3.48 eV), the reduction of OH to H 2 O is energetically unfavorable. Since OH reduction determines the overpotential for the four-electron process, 21 to promote the OH reduction, additional externally supplied energy would be needed, and therefore a relatively large overpotential would be resulted in.…”

Electron Transfer to the Trinuclear Copper Cluster in Electrocatalysis by the Multicopper Oxidases

“…4,5 The overpotential required for the ORR is remarkably small in the high potential MCOs, leading to their importance as heterogeneous catalysts for constructing efficient biocathodes in fuel cells. 6,7 The mechanism of homogeneous catalysis in MCOs, including high potential MCOs, has been well defined through spectroscopic and computational studies. [8][9][10][11][12] In the catalytic cycle, the T1 site is the primary electron acceptor which receives electrons from the reducing substrates and transfers them to the TNC through a Cys-His superexchange pathway.…”