  We reveal a correlation between the M-X bond energy descriptor EMX for the
optimal catalyst in a family of stoichiometry MiXj, and an intensive quantity
defined as the standard enthalpy of the catalyzed reaction normalized to one
mole of element X transferred by this reaction from reactants to products. M is
a transition element, and the stoichiometry MiXj is fixed at the solid/fluid
interface by the reaction conditions. We illustrate this for a relevant set of
reactions involved in solar energy and industrial applications such as oxygen
evolution, oxygen reduction and hydrogen evolution in electrolysis,
hydrodesulfurization of thiophene, methanation of CO, hydrogenations of
aromatics and alkenes, selective oxidation of methane, and ammonia synthesis
and decomposition. We propose a quantitative model to explain this unexpected
connection: this key finding and its interpretation should accelerate in silico
discovery of catalysts.
