Positive phosphorous effect during co-processing of pyrolysis bio-oils and S-content model compounds over sulfide NiMo/P/HMS-Al catalysts

Abstract

This article is focused on the problem of the inhibition of the hydrodeoxygenation (HDO) reaction by competitive adsorption of the S-containing compounds on the active sites. The phosphorous effect during co-processing of pyrolysis bio-oils and S-content model compounds over sulfide NiMo/P/HMS-Al catalysts was investigated. A series of NiMo catalysts supported on mesoporous P(x)/HMS-Al materials were prepared and characterized by several techniques. Guaiacol (GUA) was considered as a pyrolysis bio-oils model compound, while the dibenzothiophene (DBT) was used as a model molecule of S-content. The activity test revealed that support modification with 1.1 wt% of P (NM-P1.1) decreased the inhibition of HDO reaction by co-adsorption of DBT on the active sites. With the most active NM-P1.1 catalyst, the formation of a less susceptible to coke formation product (phenol) was favored. The main superiority of sulfided NM-P1.1 catalyst comes from the support decoration with P2O5 nanoparticles leading to its highest Brønsted acidity, the surface enrichment with metal sulfide species as well as with the diminishing of Al leaching from the framework of support during the HDO reaction. The activity tests demonstrated that support modification with phosphorous is an efficient method to solve the problem of the HDS inhibition by the HDO reaction.