MaxKinEff: A Collision Theory-Based Approach for Analyzing Turnover Frequency and Turnover Number in Catalytic Processes.

ABSTRACT

The efficiency of catalysts relies on comprehending the underlying kinetics that govern their performance. Under the steady-state regime, the "rate" is referred to as the turnover frequency, where the reaction rate is first order with respect to catalysts. Here, we introduce the Maximum Kinetic Efficiency (MaxKinEff ) model, grounded in collision theory, to predict efficiency based on maximum turnover frequency, 𝛤max TOF0 and maximum turnover number, 𝜏max TON0. The model was applied to molecular water oxidation using twenty-six transition metal catalysts from the first (3d), second (4d), and third (5d) rows. A thorough investigation reveals that [Ru(pda)(Br-py)2] (pda = 1,10-phenanthroline-2,9-dicarboxylate; Py = pyridinophane) exhibits a notable 𝛤max TOF0 of 1176.87 × 10-5 s-1 due to its larger collision diameter (σ𝑅𝐶) and lower activation energy (E𝑎). Importantly, the trend in the computed 𝜏max TON0 values aligns with experimental TON, 𝜏experimental TON validating the model's accuracy. For instance, [Cp∗Ir(κ2-N,O)NO3] is identified by MaxKinEff as a standout performer, with the normalized maximum computed TON, 𝜏max TON0 resembling the experimental TON, 𝜏experimental TON = 2000.