Regulation of surface hydrophobicity and metal dispersion on Pt-based catalyst for the boosted hydrodeoxygenation of guaiacol into bio-hydrocarbons

Abstract

Transformation of lignin-derived feedstocks into valuable hydrocarbons is of significant importance but still challenging. This work investigates the hydrodeoxygenation (HDO) of lignin compound guaiacol on Pt-based catalysts with improved surface hydrophobicity and metal dispersion for the first time. The efficiency of guaiacol hydrodeoxygenation into hydrocarbons over Nb2O5-modified Pt-based catalyst reaches 51 %, nearly doubling that over unmodified Pt/γ-Al2O3 catalyst (25 %). On the one hand, Nb2O5 causes the decrease of hydroxyl groups on catalyst, leading to the enhanced hydrophobicity of catalysts, which increases the reaction rate of guaiacol into hydrocarbons on unit of Pt metal sites. On the other hand, Nb2O5 strengthens the metal-support interaction, which minimizes the size of Pt nanoparticles, providing more exposed metal sites, thus leading to a higher hydrocarbons yield on catalyst. However, excess introduction of Nb2O5 leads to partial coverage of Pt metal sites, resulting in decreased yield of hydrocarbons. Furthermore, the routes of guaiacol HDO reaction over modified Pt-based catalysts are investigated. This work further illustrates the influence of catalyst surface properties on the HDO process of lignin compound, and thereby provides a promising approach for adjustment of catalyst surface properties in order to promote water-liberated reactions.