title: Mesoporous matrix encapsulation for the synthesis of monodisperse Pd5P2 nanoparticle hydrodesulfurization catalysts.
abstract: The synthesis of monodisperse 5-10 nm Pd5P2 catalytic particles by encapsulation in a mesoporous silica network, along with preliminary data on hydrodesulfurization (HDS) activity, is reported. Precursor Pd-P amorphous nanoparticles are prepared by solution-phase reaction of palladium(II) acetylacetonate with trioctylphosphine at temperatures up to 300 °C. Direct crystallization of Pd5P2 in solution by increasing the temperature to 360 °C leads to sintering, but particle size can be maintained during the transformation by encapsulation of the amorphous Pd-P particles in a mesoporous silica shell, followed by treatment of the solid at 500 °C under a reducing atmosphere, yielding Pd5P2@mSiO2. The resultant materials exhibit high BET surface areas (>1000 m(2)/g) and an average pore size of 3.7 nm. Access to the catalyst surface is demonstrated by dibenzodithiophene (DBT) HDS testing. Pd5P2@mSiO2 shows a consistent increase in HDS activity as a function of temperature, with DBT conversion approaching 60% at 402 °C. The ability to control particle size, phase, and sintering is expected to enable the fundamental catalytic attributes that underscore activity in Pd5P2 to be assessed.
authors.affiliation: Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
authors.forename: Galbokka H
authors.initials: GH
authors.lastname: Layan Savithra
authors.forename: Richard H
authors.initials: RH
authors.lastname: Bowker
authors.forename: Bo A
authors.initials: BA
authors.lastname: Carrillo
authors.forename: Mark E
authors.initials: ME
authors.lastname: Bussell
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Brock