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Communication Dans Un Congrès Année : 2019

Synergetic Effect of Manganese on the HDS and HDO Properties of Ni-Promoted MoS2/Al2O3

A. Lopez-Benitez
  • Fonction : Auteur
I. Vazquez-Garrido
  • Fonction : Auteur
A. Guevara-Lara

Résumé

Sulfide NiMo/Al2O3 catalysts have been herein modified by adding different amounts of manganese as dopant (0.1-5.0 mol % as MnO) at several pHs of impregnation of the Ni and Mo precursors (5, 7 or 9) using a sol-gel approach to form directly Mn-Al2O3 supports. The resulting different sulfide solids were then evaluated in the HDS of dibenzothiophene and in the HDO of waste cooking oil. A direct influence of the oxidation state of Mn on the nature of the Mo oxide species is observed showing particularly that formation of Mn3+ should be avoided since forming NiMnO spinel. Optimum activity is reached at a loading of 1.0 mol % as MnO with Mn leading to weaker support interaction, higher sulfidation rate and higher active NiMo phase. Adding Mn in optimized conditions leads to turnover frequencies twice higher for NiMo catalysts and to a strong direct synergetic effect of Mn towards the NiMoS phase. Results were also acquired during the HDO of a waste cooking oil showing again a strong beneficial effect of Mn on the NiMo phase at a manganese content of 1.0 mol % with an activity 50% higher than using Mn-free catalysts. However, the pH of impregnation used also influence the final HDO mechanism. While if impregnation occurs at pH=9, the C-O bond rupture of free fatty acids in alkanes is favored, impregnation at pH=5 leads to a more favored transformation of triglycerides into free fatty acids. In terms of selectivity, if impregnation is performed at pH=9, decarboxylation processes can be completely suppressed. A strong synergetic effect of manganese on the HDS and HDO properties of NiMo/Al2O3 catalysts has then been observed showing that Mn is a very interesting dopant improving the hydrotreating properties of MoS2-based catalysts making these solids highly suitable for converting O-containing molecules into useful biofuels.
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Dates et versions

hal-02276467 , version 1 (02-09-2019)

Identifiants

  • HAL Id : hal-02276467 , version 1

Citer

G. Berhault, A. Lopez-Benitez, I. Vazquez-Garrido, A. Guevara-Lara. Synergetic Effect of Manganese on the HDS and HDO Properties of Ni-Promoted MoS2/Al2O3. ACS Fall Meeting 2019, Aug 2019, San Diego, United States. ⟨hal-02276467⟩
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