The error in the gas-phase reaction energies is typically caused by the inaccuracy of common GGA xc functionals, which are on the order of 30 to 50 kJ mol -1 67 . When computing the reaction enthalpy of surface reactions from DFT energies, it is often assumed that error cancellation improves the accuracy . However, the degree of error cancellation can vary widely, depending on the specific reaction . Thus, we hope for error cancellation for surface reaction energies, but it is not guaranteed that surface reaction energies are accurate . Additionally, DFT calculations perform poorly for gas-phase species due to the approximate treatment of electron exchange and correlation . The most commonly used xc functionals in heterogeneous catalysis, such as BEEF-vdW and RPBE, are semi-empirical. They are specifically selected to predict experimental adsorption enthalpies, which reduces accuracy for gas-phase reaction energies 129 .