SBH17: Benchmark Database of Barrier Heights for Dissociative Chemisorption on Transition Metal Surfaces

Abstract

Accurate barriers for rate controlling elementary reactions on metal surfaces are key to understanding, controlling, and predicting the rate of heterogeneously catalyzed processes. While barrier heights for gas phase reactions have been extensively benchmarked, dissociative chemisorption barriers for the reactions of molecules on metal surfaces have received much less attention. The first database called SBH10 and containing 10 entries was recently constructed based on the specific reaction parameter approach to density functional theory (SRP-DFT) and experimental results. We have now constructed a new and improved database (SBH17) containing 17 entries based on SRP-DFT and experiments. For this new SBH17 benchmark study, we have tested three algorithms (high, medium, and light) for calculating barrier heights for dissociative chemisorption on metals, which we have named for the amount of computational effort involved in their use. We test the performance of 14 density functionals at the GGA, GGA+vdW-DF, and meta-GGA rungs. Our results show that, in contrast with the previous SBH10 study where the BEEF-vdW-DF2 functional seemed to be most accurate, the workhorse functional PBE and the MS2 density functional are the most accurate of the GGA and meta-GGA functionals tested. Of the GGA+vdW functionals tested, the SRP32-vdW-DF1 functional is the most accurate. Additionally, we found that the medium algorithm is accurate enough for assessing the performance of the density functionals tested, while it avoids geometry optimizations of minimum barrier geometries for each density functional tested. The medium algorithm does require metal lattice constants and interlayer distances that are optimized separately for each functional. While these are avoided in the light algorithm, this algorithm is found not to give a reliable description of functional performance. The combination of relative ease of use and demonstrated reliability of the medium algorithm will likely pave the way for incorporation of the SBH17 database in larger databases used for testing new density functionals and electronic structure methods.

Applicability of the Fridman–Macheret α-Model to Heterogeneous Processes in the Case of Dissociative Adsorption of N2 on the Ru Surface

“…Training data were obtained using DFT calculations with the PBE functional, as implemented in the Vienna Ab initio Simulation Package (VASP), 3 × 3 × 1 Monkhorst–Pack Γ-centered mesh of k -points, plane wave cutoff E cut = 400 eV, and pseudopotential in the form of projector augmented waves (PAW) . It should be noted that the RPBE functional appears to be a more precise functional for the N 2 + Ru system. , Nevertheless, calculated values of minimum energy barriers with PBE are 1.9 eV for flat Ru(0001) and 1.0 eV for stepped Ru(113), which are in reasonable agreement with the ones obtained using the RPBE functional. , …”

Simulating Highly Activated Sticking of H2 on Al(110): Quantum versus Quasi-Classical Dynamics

“… 14 If such calculations yield a S 0 curve that is in good agreement with a high-quality experiment, and if the dynamical model and method used were of high enough accuracy, the minimum barrier height computed with the electronic structure method should be an accurate value of the TS energy, also allowing its use for benchmarking purposes. 11 , 12 , 14 …”

“…14 If such calculations yield a S 0 curve that is in good agreement with a high-quality experiment, and if the dynamical model and method used were of high enough accuracy, the minimum barrier height computed with the electronic structure method should be an accurate value of the TS energy, also allowing its use for benchmarking purposes. 11,12,14 For DC of H 2 on a metal surface, with few exceptions 17 experiments measure S 0 , or effectively the DC probability averaged over the velocity distribution of and the rovibrational states populated in the molecular beam at the nozzle temperature (T N ) used. 18−27 With H 2 being the lightest molecule, one might think that the sticking in such experiments should be highly influenced by quantum effects like tunneling and that this should be especially true if the barrier to DC is high.…”

“…With more than 30,000 papers published annually, DFT is probably the most important electronic structure method applied to complex systems. While DFT has been tested extensively on databases of gas-phase reaction barriers, − tests − on databases of barrier heights for DC on metals , are still scarce.…”

“…In this procedure, the electronic structure method is used to generate the forces acting on the atoms (either directly in ab initio molecular dynamics or density functional molecular dynamics calculations or indirectly from a potential energy surface that was fitted to ab initio data) . If such calculations yield a S 0 curve that is in good agreement with a high-quality experiment, and if the dynamical model and method used were of high enough accuracy, the minimum barrier height computed with the electronic structure method should be an accurate value of the TS energy, also allowing its use for benchmarking purposes. ,, …”