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Computational investigations of Cu-embedded MoS2 sheet for CO oxidation catalysis

Author:
Sharma, Archana, Srivastava, Anurag, Husain, Mushahid, Khan, Mohd.Shahid
Source:
Journal of materials science 2018 v.53 no.13 pp. 9578-9588
ISSN:
0022-2461
Subject:
activation energy, adsorption, carbon monoxide, catalysts, catalytic activity, copper, energy, environmental hazards, nanosheets, oxidation, oxygen
Abstract:
Elevated amount of CO levels in the atmosphere poses serious health and environmental hazards. Oxidation of CO using suitable catalysts is one of the methods to control it. By means of DFT calculations, single Cu atom doped in S vacancy of MoS₂ nanosheet is studied for CO oxidation catalysis. Cu atom is strongly confined at the S-defective site of the MoS₂ sheet, possessing high energy barrier for the diffusion to its neighboring sites. Adsorption energy, charge transfer and orbital hybridization of CO and O₂ molecules adsorbed Cu-doped MoS₂ sheet reveal that O₂ is relatively more strongly adsorbed than CO. High adsorption energy of O₂ (− 2.115 eV) and large charge transfer between O₂ and Cu–MoS₂ sheet (0.493e), compared to CO, make O₂ adsorption more favorable, which extenuates CO poisoning and hence helps in the efficient CO oxidation process. The complete oxidation of CO takes place in two steps: [Formula: see text] with activation energy of 0.201 eV, succeeded by [Formula: see text] without any energy barrier. Our results show that the basal plane of MoS₂ sheet gets activated by embedding it with Cu metal, which can catalyze CO oxidation reaction effectively and without poisoning issues. The high activity, stability and low cost features can possibly encourage fabricating MoS₂-based catalysts for CO oxidation reaction.
Agid:
5932193