Methanol formation by catalytic hydrogenation of CO₂on a nitrogen doped zinc oxide surface: an evaluative study on the mechanistic pathway by density functional theory

Abstract

An investigation of the nature of adsorption of H 2 O and CO 2 on a nitrogen doped zinc oxide cluster surface and the resultant reaction between them has been performed using hybrid density functional theory (DFT) calculations at the B3LYP level of theory in a vacuum. The stable chemisorption modes of CO 2 and H 2 O on metal, oxygen and nitrogen sites were examined. The calculated adsorption energies reveal that the formation of CO 2 À attached to N is the most favorable process for CO 2 on the Zn 18 O 17 :N cluster surface, with a binding energy of À1.86 eV. The water molecule spontaneously dissociates on the same surface to produce chemisorbed H* and *OH with an interaction energy of À0.77 eV. The model calculations rationalize the hydrogenation of CO 2 by H 2 generated from H 2 O on the cluster surface.Thermodynamically favorable reaction pathways for the formation of methanol on the catalytic surface in a vacuum were proposed. Among the three pathways, methanol formation follows the carbamate route. The carbamate formed undergoes hydrogenation to generate COOH* units, followed by its exothermic decomposition to *CO attached to N and *OH. Further hydrogenation of CO ultimately yields methanol. All of the above steps were computationally evaluated.

Sensing and conversion of carbon dioxide to methanol using Ag-decorated zinc oxide nanocatalyst

“…The desorption/formation energy 52,53 of the product methanol (CH 3 OH) is calculated to be À2.23 eV, which is more negative than that of the previously reported studies, 54 thus indicating an exothermic reaction and the superiority of the ZnO nanocage for methanol production.…”

Nitrogen doped In2O3–ZnO nanocomposite mesoporous thin film based highly sensitive and selective ethanol sensors

“…16,32 The peak corresponding to the adsorbed surface hydroxyl has been more pronounced for the IZO 50 film compared to the IZON films, which is attributed to reduced adsorption of water molecules on the nitrogen doped metal oxides. 33,34 The ratios of areas under curves A V /A L (A V and A L are the area under the curve for non-stoichiometric and lattice oxygen, respectively) for IZON 25, IZON 50, IZON 75 and IZO 50 have been estimated to be 1.12, 1.17, 1.08 and 0.85 respectively. The increase in oxygen vacancy (related to non-stoichiometric oxygen) in the IZON films has been accredited to doping.…”

“…Further theoretical studies have confirmed the preferential adsorption of oxygen compared to water molecules in nitrogen doped metal oxides, which also reduces the influence of water molecules on the sensing performance of nitrogen doped metal oxide under high humid conditions. 34,41 The ethanol sensing response of IZON 50 has been examined over an extended period. As shown in Fig.…”

Adsorption of SF6 Decomposed Products over ZnO(101̅0): Effects of O and Zn Vacancies

“…The CO 2 catalytic fixation process on different surfaces was studied by Tang et al, and the binding strength is the inverse of the stability of the chosen surface . Not only that, the (101̅0) or (0001) surface can be an effective medium for urea adsorption and decomposition, methanol reaction or other organic reaction, − and small-molecule adsorption. , More than the specified crystal indices, the metal oxide nanoparticles were also used to evaluate the gas-sensing properties. By doping N atom on the surface, the cohesive energy between the O 3 /NO 2 molecule and the ZnO nanoparticle can be significantly increased .…”