مقاله The influence of citric acid on the synthesis and activity of high surface area MoP for the hydrodeoxygenation of 4-methylphenol : تی پی بین

خلاصه مقاله

The influence of citric acid on the synthesis and activity of high surface area MoP for the hydrodeoxygenation of 4-methylphenol

Unsupported, high surface area MoP was synthesized by adding citric acid (CA) to solutions of ammonium heptamolybdate and diammonium hydrogen phosphate followed by drying (397 K), calcination (773–973 K), and reduction in H₂ (923 K). A tetrameric Mo citrate precursor was formed after drying which decomposed into a monomer of the form, Mo(C4H₅O₃CN)O₂·HPO4 following calcination. Reduction of this monomer produced CH₄, CO, CO₂, NH₃, H₂O, and MoP. The C content of the reduced MoP-CA catalysts decreased from 12.8 to 4.0 wt% as the calcination temperature increased from 773 to 973 K, whereas the surface area decreased from 136 m2/g to 53 m²/g and the MoP particle size increased from 5 to 9 nm, respectively. The residual C acted as a structural promoter of the calcined samples, limiting agglomeration of the MoP crystallites during reduction so that nanoparticles (5–9 nm) of MoP were produced. The HDO of 4-methylphenol over the MoP-CA catalysts was found to be structure insensitive with an initial turnover frequency (TOF) of 0.079 s⁻¹ at 623 K and 4.4 MPa H₂. The ratio of hydrogenation to direct deoxygenation of 4-methylphenol (TOF_HYD:TOF_DDO = 0.78:1) was independent of the MoP particle size and greater than that observed over MoS₂.

نویسندگان

Victoria M.L. Whiffen [ Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z3, Canada ]

Kevin J. Smith [ Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z3, Canada ]

Suzana K. Straus [ Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada ]

کلمات کلیدی

Hydrodeoxygenation Hydrogenation 4 Methylphenol Structure sensitivity Molybdenum phosphide Catalyst preparation Citric acid Molybdenum citrate Unsupported catalyst

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2012 Applied Catalysis A: General

The scope of Applied Catalysis A: General includes the following:Scientific understanding of any catalytic phenomenon .Phenomena of relevance to current industrial processes, processes under industrial development or of interest for future commercial applications are particularly welcome. Heterogeneous, homogeneous and biocatalysts are included .Research investigating catalytic actions of heterogeneous, homogeneous, biological and natural systems are especially encouraged. Scientific aspects of preparation, activation, aging, deactivation, rejuvenation, regeneration and start up transient effects of commercially interesting or representative model catalysts. Scientific methods of characterization of catalysts, especially if they are applicable to industrial catalysts .Chemical engineering aspects relevant to an improved understanding of catalytic phenomena or application to catalysis. Results involving a joint approach by chemical engineering and catalytic science are particularly welcome. New catalysts, catalytic reactions, catalytic routes and processes of potential practical interest. Catalysis and catalytic processes for sustainable practices, including sustainable energy supply and consumption processes, and sustainable chemicals production.

حوزه های تحت پوشش : Petrochemical industry , Catalytic Science , chemical scientists in both industrial and academic fields