Decomposition of methanol on nanosized tube of magnesium oxide: A theoretical study

The interaction of a methanol molecule with an MgO nanotube was investigated by using density functional calculations. It was mainly found that (1) the adsorption process is associative in the exterior surface and dissociative at the ends of the tube; (2) in the most stable states, calculated adsorption energies are about −29.5 and −35.6 kcal/mol for associative and dissociative adsorptions, respectively; (3) a small barrier energy of 5.6 kcal/mol must be overcome to get the final structure in dissociative process; (4) cleavage of O-H bond of methanol is more favorable than C-O bond cleavage about 7.0 and 8.5 kcal/mol, thermodynamically and kinetically, respectively; (5) the dissociative processes influence the electronic properties of MgO nanotube more than associative processes; and (6) HOMO/LUMO gap of the tube is significantly reduced from 4.63 to 3.94 eV upon the O-H cleavage.