Gas-Phase Errors Affect DFT-Based Electrocatalysis Models of Oxygen Reduction to Hydrogen Peroxide

Abstract

Electrochemical production of H2O2 is more benign and affordable than the conventional route, yet its adoption requires the discovery of robust, cost-effective catalysts. DFT-based models lead to conspicuous breakthroughs but had some known limitations, for instance the poor description of molecules with certain chemical bonds. Here, the errors in H2O2 and O2 displayed by various GGAs, meta-GGAs and hybrids were assessed and semi empirically corrected. The errors in O2 with respect to experiments were in the range of −0.95 to −0.22 eV, whereas those in H2O2 spanned from −0.53 to −0.04 eV. Thus, single and double O−O bonds were poorly described in general, and the errors were nearly twice as negative for double bonds. Furthermore, these errors introduced large deviations in the predictions of free energies for O2 reduction to H2O2, and the equilibrium potentials and optimal adsorption energies of *OOH could either be sizably overestimated or underestimated.