Kinetic Mechanism of Methanol Decomposition on Ni(111) Surface:  A Theoretical Study

Abstract

The decomposition of methanol on the Ni(111) surface has been studied with the pseudopotential method of density functional theory-generalized gradient approximation (DFT-GGA) and with the repeated slab models. The adsorption energies of possible species and the activation energy barriers of the possible elementary reactions involved are obtained in the present work. The major reaction path on Ni surfaces involves the O-H bond breaking in CH(3)OH and the further decomposition of the resulting methoxy species to CO and H via stepwise hydrogen abstractions from CH(3)O. The abstraction of hydrogen from methoxy itself is the rate-limiting step. We also confirm that the C-O and C-H bond-breaking paths, which lead to the formation of surface methyl and hydroxyl and hydroxymethyl and atom hydrogen, respectively, have higher energy barriers. Therefore, the final products are the adsorbed CO and H atom.

Adsorption of Methanol and Methoxy on Cu(111) Surface: A First‐principles Periodic Density Functional Theory Study

“…23 It should be noted that, in the coadsorption structure of CH 3 O and H on Cu(111) surface, the methoxy species and hydrogen atom are placed above the two closest fcc hollow sites (Figure 3, product), and the structure of product is similar to that adsorbed on Ni(111) surface. 20 The adsorption energy of product is 19.14 kJ/mol lower than that of the reactant, suggesting that molecular adsorption should be the precursor of dissociative chemisorption.…”

“…It was believed that the adsorption of methanol appeared to occur via a donation of a lone pair of electrons from the oxygen to the metal surface. 20 Clean copper surfaces exhibit a relatively low activity for methanol oxidation. At low surface temperatures of about 100 K only adsorbed molecular methanol was observed experimentally on Cu surfaces.…”

Unravelling the Mechanism of Glycerol Hydrogenolysis over Rhodium Catalyst through Combined Experimental–Theoretical Investigations

“…Some of us have already investigated from density functional theory (DFT) calculations the adsorption of glycerol and its dehydration intermediates at the surfaces of NiA C H T U N G T R E N N U N G (111), Rh-A C H T U N G T R E N N U N G (111) and PdA C H T U N G T R E N N U N G (111) to identify the key points that control the selectivity of the hydrogenolysis reaction. [38] The adsorption and reactivity of other small oxygenated compounds such as methanol [39][40][41][42][43][44][45] (MeOH) or ethanol [46][47][48][49][50][51][52][53][54][55][56] (EtOH) on the model surfaces of transition metals can also provide helpful clues. Despite the tremendous number of works realised until now, only a few have performed a mixed experimental and theoretical approach (using DFT) to gain further insights into the reactivity of glycerol.…”

Reaction mechanism of methanol decomposition on Pt‐based model catalysts: A theoretical study

“…Vibrational frequencies are calculated by numerical differentiation of the forces using a second order finite difference approach with a step size of 0.015 Å . 32,33 The Hessian matrix is mass weighted and diagonalized to yield the frequencies and normal modes of the system.…”