Zirconium Phosphate Heterostructures as Catalyst Support in Hydrodeoxygenation Reactions

Abstract

Abstract:A porous phosphate heterostructure (PPHs) formed by a layered zirconium(IV) phosphate expanded with silica galleries was prepared presenting a P/Zr molar ratio equal to 2 and a (Si + Zr)/P ratio equal to 3. This pillared zirconium phosphate heterostructure was used as a catalyst support for bi-functional catalysts based on noble metals (Pt or Pd) and molybdenum oxide containing a total metallic loading of 2 wt % and Pt(Pd)/Mo molar ratio equal to 1. The catalysts prepared were characterized by different experimental techniques and evaluated in the hydrodeoxygenation (HDO) reaction of dibenzofuran (DBF) as a model compound present in biomass derived bio-oil, at different reaction pressures. The catalyst characterization evidenced that a high dispersion of the active phase can be achieved by using these materials, as observed from transmission electron microscopy (TEM) characterization, where the presence of small particles in the nanometric scale is noticeable. Moreover, the textural and acidic properties of the phosphate heterostructure are barely affected by the incorporation of metals into its structure. Characterization results evidenced that the presented material is a good candidate to be used as a material support. In both cases, high conversions and high selectivities to deoxygenated compounds were achieved and the active phase played an important role. Thus, Pt/Mo presented a better hydrogenolysis capability, being more selective to O-free products; whereas, Pd/Mo showed a greater hydrogenation ability being more affected by changes in pressure conditions.

Sustainable Porous Heterogeneous Catalysts for the Conversion of Biomass into Renewable Energy Products

“…171 Furthermore, Pd/Pt and molybdenum oxide supported on layered Zr(IV) phosphate-silica composite material have also been employed as catalysts for the deoxygenation of bio-oil into liquid hydrocarbons. 172 The introduction of silica into layered Zr(IV) phosphate enhances the specific surface area and improves the fine dispersion of reactive metallic sites, facilitating the reduction process. Parallel to this, the synthesis of organically functionalized porous aluminum phosphonate materials (Ph-ALPO-1 and Ph-ALPO-2) is presented as catalysts for converting carbohydrates from biomass into 5-HMF.…”

“…Additionally, Pd and molybdenum phosphate nanoparticles finely dispersed over a silica support have been successfully utilized by O’Hare et al for the hydrodeoxygenation of biomass-derived lignin, cellulose, and hemicellulose into liquid alkanes with high yield and selectivity . Furthermore, Pd/Pt and molybdenum oxide supported on layered Zr(IV) phosphate-silica composite material have also been employed as catalysts for the deoxygenation of bio-oil into liquid hydrocarbons . The introduction of silica into layered Zr(IV) phosphate enhances the specific surface area and improves the fine dispersion of reactive metallic sites, facilitating the reduction process.…”

Zirconia-Based Solid Acid Catalysts for Biomass Conversion

“…The evolution of the research about ZP starts from understanding its synthesis methods and structures to the designing and fabrication of novel structures and the exploration of their functions and applications in recent years . Due to the high acidity, ease of fabrication, modification, functionalization, high water tolerance, high thermal stability, and easy recovery, ZP has been extensively investigated for a variety of acid-catalyzed reactions such as isomerization, hydrodeoxygenation, dehydration, and ester hydrolysis reactions. ,, Moreover, because of the high proton mobility on the surface, ZP also gives rise to a high proton conductivity which makes it a hot candidate for proton-conducting materials. , To date, ZP has been recognized as one of the most popular and well-studied materials in the family of transition metal phosphates …”