Comparing B3LYP and B97 Dispersion‐corrected Functionals for Studying Adsorption and Vibrational Spectra in Nitrogen Reduction

Abstract

Electrochemical ammonia synthesis is being actively studied as a low temperature, low pressure alternative to the Haber-Bosch process. This work studied pure iridium as the catalyst for ammonia synthesis, following promising experimental results of Pt-Ir alloys. The characteristics studied include bond energies, bond lengths, spin densities, and free and adsorbed vibrational frequencies for the molecules N 2 , N, NH, NH 2 , and NH 3. Overall, these descriptive characteristics explore the use of dispersioncorrected density functional theory methods that can model N 2 adsorption-the key reactant for electrochemical ammonia synthesis via transition metal catalysis. Specifically, three methods were tested: hybrid B3LYP, a dispersion-corrected form B3LYP-D3, and semi-empirical B97-D3. The latter semiempirical method was explored to increase the accuracy obtained in vibrational analysis as well as reduce computational time. Two lattice surfaces, (111) and (100), were compared. The adsorption energies are stronger on (100) and follow the trend E B3LYP > E B3LYP-D3 > E B97-D3 on both surfaces.

Density functional theory study of Mobius boron-carbon-nitride as potential CH 4 , H 2 S, NH 3 , COCl 2 and CH 3 OH gas sensor

“…The B3LYP method cannot describe the dispersion among molecules to provide higher accuracy of adsorption [24]; hence we incorporated the dispersion-corrected B3LYP-D3 calculation to obtain the dispersion-corrected adsorption energy ( E Ads, Disp ) from the following equation:EAds, Disp=Efalse(normalMBCN+normalgas,normalDispfalse)−Efalse(normalMBCN,normalDispfalse)−Efalse(normalgas,normalDispfalse),where E (MBCN + gas, Disp) , E (MBCN, Disp) and E (gas, Disp) are the dispersion-corrected energy of the MBCN + gas complex structure, pristine MBCN and gas molecules, respectively [19,24,25].…”

Solution and Solvent‐Free Stopper Exchange Reactions for the Preparation of Pillar[5]arene‐containing [2] and [3]Rotaxanes

“…Solvation effects are also quite limited on the distortion energies of ( H.G1 ) and ( H.G2 ). The interaction energies were actually not considered at the B3LYP level as dispersive interactions between molecules are not well described with this functional [27] . For this reason, the structures of ( H.G1 ) and ( H.G2 ) were further optimized at the ωB97X−D/6‐31G* level in THF as the ωB97X−D functional includes empirical corrections for long‐range dispersive interactions [28] …”

“…The interaction energies were actually not considered at the B3LYP level as dispersive interactions between molecules are not well described with this functional. [27] For this reason, the structures of (H.G1) and (H.G2) were further optimized at the ωB97XÀ D/6-31G* level in THF as the ωB97XÀ D functional includes empirical corrections for long-range dispersive interactions. [28] The computed E Int value is 15.8 kJ mol À 1 more favorable for G1 when compared to G2.…”

Optimizing photovoltaic performance of squaraine derivative dyes: a DFT study on different anchoring groups

“…Thus, the size of the cluster proposed here can be considered representative model of TiO 2 . [69][70][71] The geometry optimizations of Dye@(TiO 2 ) 14 were conducted using LANL2DZ effective core potential and its accompanying basis set for Ti atom, while the other atoms were treated with the double-x basis set 6-31G(d) and the so-called dispersion-corrected B3LYP functional, B3LYP-D3, recommended for accounting for weak interactions, including van der Waals dispersive forces, 72,73 which play a signicant role in the adsorption process between the TiO 2 surface and the dye. The solvation effect was considered using the SMD model.…”