Adsorption energies (𝐸 𝑎𝑑𝑠 ) of nitric oxide and nitrite were calculated as 𝐸 𝑎𝑑𝑠 = 𝐸 𝑎𝑑𝑠+𝑠𝑙𝑎𝑏 -𝐸 𝑠𝑙𝑎𝑏 -𝐸 𝑎𝑑𝑠 𝑔 [4] where 𝐸 𝑎𝑑𝑠+𝑠𝑙𝑎𝑏 is the total energy of slab with the adsorbate, 𝐸 𝑠𝑙𝑎𝑏 is the total energy of clean metal slab, and 𝐸 𝑎𝑑𝑠 𝑔 is the total energy of most stable configuration of adsorbate in gas phase. Free energies of adsorption were determined from DFT-calculated adsorption energies corrected with zero-point energy (ZPE) and standard state entropy corrections (T*S) using the harmonic oscillator approximation at 293K.