Our theoretical calculations identify nitric oxide free energy of adsorption ( Δ𝐺 𝑁𝑂 ) becomes more negative as TM Ed approaches EF (Figure ), in-line with descriptions of other simple adsorbates. Dissociation activation barriers decrease with reaction enthalpy (Δ(𝐸 𝑁 +𝑂 𝐸 𝑁𝑂 )) and Ed vs EF (Supplementary Figure ), in-line with Brønsted-Evans-Polanyi (BEP) scaling relationships. This suggests preferential associative adsorption on weak-binding TMs (e.g. Ag and Cu; Δ𝐺 𝑁𝑂 < Δ𝐺 𝑁 +𝑂 ) and dissociative adsorption on strongbinding TMs (e.g. Ni0.68Cu0.32, Ni, Co, and Fe; Δ𝐺 𝑁𝑂 > Δ𝐺 𝑁 +𝑂 ), in line with prior literature on stepped surfaces (Supplementary Figure ) and in vacuo single crystal adsorption studies. Assuming N * can only be hydrogenated to ammonium as a terminal reduction product, this increased preference towards dissociative nitric oxide adsorption could lead to enhanced selectivity towards ammonium on TMs where Ed approaches and overcomes EF. Data for Ed vs EF adapted from Ref. .