Impact of Intrinsic Density Functional Theory Errors on the Predictive Power of Nitrogen Cycle Electrocatalysis Models

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

“…However, such an ad hoc procedure may not work for reactions in which more than one substance has associated gas‐phase errors. For instance, that is the case for the electrochemical reduction of CO 2 to CO (where both CO 2 and CO display large gas‐phase errors) [34,36,37] and reactions within the nitrogen cycle [35,63] . For the 2e − ORR, as shown in Figures 2–3, such a procedure impedes discerning the O 2 errors from those of H 2 O 2 , which are convoluted as shown in Equation (4).…”

Automated versus Chemically Intuitive Deconvolution of Density Functional Theory (DFT)-Based Gas-Phase Errors in Nitrogen Compounds

“…For example, it was shown in a recent work for electrochemical ammonia synthesis and electrochemical nitric oxide reduction to hydroxylamine that gas-phase corrections modify the predicted overpotentials, Sabatier-type volcano plots, and the ordering of catalytic activities among the analyzed materials. 34 In addition, gas-phase corrections have also been shown to improve the prediction of equilibrium and onset Second column (energies denoted with a superscript "exp") shows experimental formation energies; the third column (energies denoted with a superscript "ONC") contains the DFT-calculated formation energies with O 2 and N 2 corrections. The fourth, fifth, and sixth columns give the final formation energies upon applying the sequential method in Figures 1 and 2 (energies denoted with a superscript "seq") and automated optimizations 1 and 2 in Figures 3 and 4, respectively (energies denoted with superscripts "AO1" and "AO2").…”

“…44,45 We did not incorporate heat capacity contributions to the formation energies in eq 3, because their energy change has been shown to be small in the range of 0 to 298.15 K 31,46 (see further details in section S6 in the Supporting Information). We note that previous works showed that the differences between experimental and calculated Δ f ZPE are negligible for various H x N y O z compounds, 34 such that the errors can be entirely assigned to Δ f E DFT . The experimental Gibbs energies used in eq 2 to compute the errors are also taken from thermodynamic tables.…”

“…Exchange-correlation functionals based on the generalized gradient approximation (GGA) are widely used to study catalytic systems in view of their affordable computational requirements and reasonable predictions of metal bulk and surface properties. − Although the limitations of GGAs in describing the energetics of molecules are well-known, − semiempirical and fully computational schemes can be devised to rapidly correct them. − Correction schemes generally seek to identify specific groups of atoms or functional groups that systematically contribute to the total errors of different molecules. While the errors can mostly be attributed to poor descriptions of the exchange contribution to the total DFT energy in molecules with multiple bonds and/or strongly interacting lone pairs, , the detection and quantification of systematic errors enables otherwise modest GGA functionals to produce accurate yet inexpensive predictions.…”

Ab Initio Thermodynamic Stability of Carbide Catalysts under Electrochemical Conditions

“…Still, it is important to recall that also this upper end is only an approximate descriptor and one would realistically expect small, but nonzero overpotentials for CO2RR anyway. Even though errors from the approximate DFT functional − will largely cancel out in the surface free energy differences and trends considered here, an additional uncertainty will also arise from there. If one therefore rather identifies the potential range – 1 V < U < −0.25 V vs RHE as a likely window of operation where selectivity is not yet completely eliminated by the competing HER, then this would largely be met by the deduced stability windows for the here considered group VB and VIB carbides, as seen in Figure .…”