• Surface acidity in promoted molybdena and tungsta hydrodesulphurisation catalysts

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      https://www.ias.ac.in/article/fulltext/jcsc/102/02/0117-0129

    • Keywords

       

      Surface acidity; molybdena; tungsta; hydrodesulphurisation catalyst; ammonia

    • Abstract

       

      Acidity of Ni- and Co-promoted molybdena and tungsta hydrodesulphurisation (HDS) catalysts have been determined by volumetric adsorption of ammonia. A direct correlation between the adsorption of ammonia, and hence the acidity, and the HDS activity could be observed for reduced catalysts A relation between ammonia adsorption and anion vacancy concentration is thus indicated, as the latter is related to HDS activity. Contrary to unpromoted molybdena there is a decrease in acidity on sulphidation of Ni-promoted molybdena catalyst. This decrease is attributed to the influence of, Ni in suppressing the formation of anion vacancies by catalysing the crystallisation of MoS2. Promoted tungsta catalysts were found to have lower acidities as compared to promoted molybdena catalysts, which is consistent with their lower desulphurisation activity.

    • Author Affiliations

       

      M O Alias1 V Srinivasan1

      1. Department of Chemistry, Indian Institute of Technology, Madras - 600 036, India
    • Dates

       
  • Journal of Chemical Sciences | News

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