Resolving the dual-pathway adsorption mechanism of methanol on Ni(100) via dynamic Monte Carlo simulations and...

The adsorption mode of methanol on Ni(100)-whether molecular or dissociative-has been a central unresolved question in surface chemistry for over four decades. Here, we combine Dynamic Monte Carlo (DMC) simulations with Response Surface Methodology (RSM) to resolve this mechanistic ambiguity and simultaneously optimize hydrogen yield. A lattice-gas model on a 350 × 350 grid simulates all elementary steps of methanol decomposition, with kinetic parameters rigorously validated against experimental TPD spectra (R ² = 0.9897) and independent isothermal data. Our simulations unequivocally demonstrate that neither molecular nor dissociative adsorption alone reproduces the experimental H₂ and CO desorption profiles; only a dual-pathway model incorporating both channels simultaneously matches all observables. This finding provides the first definitive resolution to a long-standing mechanistic controversy in transition metal surface chemistry. Using a central composite RSM design, we investigate the influence of temperature, pressure, and time on hydrogen yield, identifying optimal conditions (379.7 K, 3.50 µPa, 107.8 s) that achieve 95.5% yield-in excellent agreement with model predictions (96.8%, within 95% CI). Sensitivity analysis confirms <1.5% yield variation under ±20% kinetic parameter perturbation, underscoring the robustness of our mechanistic conclusions. The validated kinetic network delivers a quantitative foundation for rational catalyst design and hierarchical microkinetic modeling, advancing both fundamental understanding and practical applications of alcohol decomposition on nickel surfaces.