Reagent molecules must bind to the catalyst surface before they can
react. Bind too weakly and they leave before reacting; bind too strongly
and the surface stays covered with unreactive product ("poisoned"). The
Sabatier principle says the best catalyst binds the reactant just strongly
enough — plotting rate against binding energy always produces a volcano
shape, and screening (DFT/ML) is really a search for that summit.
TOF(ΔE) ≈ A · exp(−α|ΔE − ΔE_opt| / kT)
θ (coverage) rises with |ΔE|, ΔE_opt ≈ −1.6 eV here
- Adsorption energy ΔE — how strongly the reactant binds this catalyst's surface sites.
- Temperature — higher T speeds every step but also empties weakly-bound sites faster.
- Feed flux — how often fresh reactant molecules arrive to attempt binding.
- Metal presets — Ni, Pd, Pt, Cu sit at different points on the same volcano curve.
The right-hand panel plots turnover frequency against ΔE; the glowing
marker shows exactly where your current catalyst sits on the curve.