All DLPNO-CCSD(T) adsorption energies, including those obtained with individual basis sets (with and without correction for basis set superposition error) and CBS-extrapolated values, are compiled in Table .3. A comparison of def2-SVZ/def2-TZVP and def2-TZVPP/def2-QZVPP extrapolated energies shows that the former are much more negative, by about -14 kJ mol -1 , indicating that the inclusion of quadruple-zeta basis sets in the CBS extrapolation is required to obtain reliable results. First of all, it is clearly visible that identical trends across the set of dc-XC functionals are observed for all three configurations, and for both CBS-extrapolated and TZVP-MOLOPT adsorption energies, with TZVP-MOLOPT delivering systematically more negative values by about -2 to -6 kJ mol -1 . When comparing the CBS-extrapolated adsorption energies to the DLPNO-CCSD(T) reference values, the following observations can be made: