Effects of manganese promotion on reactants and intermediates of Fischer Tropsch Synthesis on a model cobalt surface-a Density Functional Theory investigation için kapak resmi
Effects of manganese promotion on reactants and intermediates of Fischer Tropsch Synthesis on a model cobalt surface-a Density Functional Theory investigation
Başlık:
Effects of manganese promotion on reactants and intermediates of Fischer Tropsch Synthesis on a model cobalt surface-a Density Functional Theory investigation
Yazar:
Gençoğlu, Merve, author.
Yazar Ek Girişi:
Fiziksel Tanımlama:
xi, 90 leaves: charts;+ 1 computer laser optical disc.
Özet:
The effects of manganese promotion on the adsorbates and specific elementary reactions of Fischer-Tropsch Synthesis (FTS) was investigated using periodic Density-Functional Theory (DFT) calculations on a close packed cobalt surface, Co(111). In particular the effects of MnO promotion on the adsorbates of CO, HCO, CH, CH2, C2H2, OH, H2O, C, O and on the reactions of direct CO dissociation, H-assisted CO dissociation and carbon hydrogenation were studied for MnO coverages of 0.25 ML and 0.11 ML. Mn was modeled in the chemical form of MnO. MnO was modeled as a singular monomer on the Co(111) surface, based on the findings from experimental studies. The results indicate that MnO promotion increases the adsorption energies of all adsorbates, except H and C2H2. In particular, CO and H2O adsorption energies increase significantly, which indicate that the selectivity increases to long chain hydrocarbons is mainly due to an increased surface coverage of CO with respect to H. The results also indicate that the relative effect of MnO on adsorption energies are strongly dependent on MnO coverage. MnO promotion is found to decrease the activation barriers for HCO and CH formation, while increasing the activation barriers for direct CO dissociation and HCO dissociation. The results point out that MnO does not promote the direct dissociation of CO and the activity increase due to Mn promotion is most probably due to a H or OH assisted CO dissociation pathway or another rate limiting step. Keywords: Density Functional Theory, Fischer-Tropsch Synthesis, Catalysis, Promoter, Cobalt, Manganese
Yazar Ek Girişi:
Tek Biçim Eser Adı:
Thesis (Master)--İzmir Institute of Technology: Materials Science and Engineering.

İzmir Institute of Technology:Materials Science and Engineering--Thesis (Master).
Elektronik Erişim:
Access to Electronic Versiyon.
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