Monte Carlo Simulation of Ethylene Hydrogenation on Pt Catalysts

Structural and Kinetic DFT Characterization of Materials to Rationalize Catalytic Performance

“…Finally, it has been found that, oppositely to what experimentally observed for the cis-but-2-ene/trans-but-2-ene gas-phase order of stability, several 52T systems containing cis-but-2-ene resulted more stable than the analogous systems involving trans-but-2-ene isomer adsorbed on the same acidic -OH sites, confirming the basis role played by the local steric hindrance, in driving molecular adsorption properties and surface reactivity in confined spaces [78][79][80][81][82].…”

IDEA: Interface dynamics and energetics algorithm

“…When the code reached the predetermined simulation times or true steady-state conditions-whose occurrence was systematically monitored along the simulation, 15,16,18,19,26,27 it finalized the results' files and ended, by following the closing instructions of the Driver box.…”

“…For this reason, it was possible to define a first level reduced sample space, rss, constituted by the complementary events 76 e h , e d , and φ, where the latter is the, already introduced (see Event Frequencies and Probabilities section), null event. Therefore, the initial run time-unit, T 1, employed to monitor the elapsing time was defined as τ = T 1 = const 1 f −1 ei , 15,16,[18][19][20][21] corresponding e i to e h or e d , the most frequent (time-updating) events, e mc . The const 1 values were chosen to have p(e h ∪ e d ∪ φ) = 1.00, being p the total probability of the first level rss and p(φ), the probability of the null event, fixed at 0.05.…”

“…This allowed us to calculate the hitting probability (see next section) and to state a starting internal clock, monitoring the system elapsing time, τ , along the occurrence of the elementary events. 15,16,[18][19][20][21] The Maxwell-Boltzmann distribution law 64 was employed to compute the energy of a CO molecule when it hit the surface. This was employed, as shown in the next section, together with information on the surface population and energy to calculate the variable sticking probability.…”

“…25 However, here, we chose to employ the simple algorithmic approach, which already showed to be able to manage the "real time" seriality of catalytic events and the consequent local energetic effects, reproducing experimental results. 15,16,18,19,26,27 In fact, many experimental findings, concerning the hydrogenation on metal catalysts of unsaturated hydrocarbons 15,16,18 of their mixtures 19,26 and of nitro-derivatives, 27 were easily reproduced and rationalized by employing the tdMC codes.…”