Establishing the role of graphite as a shaping agent of vanadium - aluminum mixed (hydr)oxides and their physicochemical properties and catalytic functionalities

摘要: This work contributes to the establishment of a scientific basis for understanding effect shaping on physicochemical properties and functionalities catalytic powders. In particular, influence graphite (G) as agent vanadium–aluminum mixed (hydr)oxides, VAlO, is presented herein. Graphite was added in different loadings (x = 1, 3, 7 wt %). VAlO-xG hydroxides were tableted then calcined obtain oxides. Both series materials characterized tested propane oxidative dehydrogenation (ODH). Correlation X-ray photoelectron spectrometry (XPS) Raman data permitted establishing that are constituted by particles physically attached amorphous VAlO structure. The hydroxide structure found be composed Al(OH)3 AlOOH linked decavanadates-, metavanadates, isolated or cluster vanadyl V═O species. Calcination caused further polymerization vanadium species into decavanate chains V2O5-like structures connected γ-Al2O3-like matrix. Though not incorporated XPS analysis showed it actively interacts with surface. Such interaction favored propylene selectivity ODH. Particularly, containing displayed higher production propene over COx at high conversion. On other hand, though boosts mechanical resistance tablets, surface area materials, determined application χ-theory, significantly decrease after calcination. trend explained considering pore widening during tableting. Finally, characterization performed recovered from crushed tablets randomly distributed within shaped catalysts.