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.