Charge influence on the first dehydrogenation of methanol by Pt_n^q (n = 1-3, q = 0, +1, -1): a computational study

Understanding the bond-cleavage ability of metal clusters is very important in various fields, such as catalysis and surface science. In this work, we performed density functional theory calculations on the first dehydrogenation process (also the key step) of methanol on Pt_n^q (n = 1-3, q = 0, +1, -1) clusters in varied charge states using quantum chemical calculations. It is shown that methanol is adsorbed much more easily to the cationic Pt_n⁺ than to the neutral and anionic Pt_n^0/-. By contrast, the intrinsic bond cleavage barriers of both C-H and O-H on the cationic Pt_n⁺ are significantly higher than on Pt_n^0/- (the only exception is the C-H bond cleavage on Pt⁺). Promisingly, injecting an electron to the neutral Pt_n⁰ to give Pt_n^- can greatly reduce the C-H/O-H bond scission barrier while maintaining appreciable adsorption energy. The charging effect can be nicely interpreted by the nature of the frontier orbitals of Pt_n^q.