not-yet-known not-yet-known not-yet-known unknown Selective oxidation of long-chain fatty alcohols into acids is an important value-added reaction. However, exploring the basic catalytic steps over Pt-based catalysts throughout the entire oxidation process is still ambiguous. In this work, we systematically investigated the synergistic mechanisms of adsorption, reaction, and diffusion over Pt/MCM-41 for normal/isomeric alcohols oxidation into acids via molecular dynamics, in-situ characterization, and experiments. Specifically, diffusion coefficients decrease with the increase of the molecular weight of normal molecules due to the increased van der Waals forces, while isomeric alcohols exhibit more complex patterns originated from the steric hindrance between Pt particles and mesopores. To quantitatively describe this pattern, a cluster size descriptor of d Pt 0 . 75 × d Pore 0 . 25 was defined. Notably, 2-ethylhexanol exhibits the best self-diffusion coefficients at the descriptor value of 3.14. Correspondingly, the oxidation of 2-ethylhexanol to 2-ethylhexanoic acid displays highest reaction conversion (68.67%) and selectivity (65.59%).

Herein, we systematically investigated the reaction mechanism of n-pentane cracking on the Ag/ZSM-5 bifunctional catalyst featuring both dehydrogenation and cracking capabilities. Specifically, overall cracking network of n-pentane was comprehensively constructed to show the roles of metal dehydrogenation sites and acid sites respectively, in which metal Ag could substitute the H of the Brønsted acid site to form the Al-O-Ag linkage with enhanced adsorption and activation of n-pentane, while Brønsted acid site with weak acid strength relay to promote cracking reaction. Thanks to this synergy of the two active sites, the apparent activation energy of n-pentane cracking to light olefins was decreased from 82.77 KJ/mol to 68.26 KJ/mol and the proportion of specific path (C5H12→H2+C5H10) in n-pentane monomolecular cracking reaction increased from 14.62% to 69.24%. In addition, 0.57Ag/ZSM-5 catalyst exhibited the conversion of n-pentane up to 67.55wt%, which improved the performance of the parent ZSM-5 by 13.42wt%.