The relationship between acidity, dispersion of nickel, and performance of Ni/Al-SBA-15 catalyst on eugenol hydrodeoxygenation

Abstract

Catalytic hydrodeoxygenation (HDO) is considered as one of the most efficient methods for lignin-derived bio-oils upgrading. To reveal the relationship between the characters of Ni/Al-SBA-15 and the catalytic activity of eugenol hydrodeoxygenation in aqueous phase, Al-SBA-15 with different Si/Al ratios were synthesized using acid free method and corresponding Ni/Al-SBA-15 catalysts were prepared by incipient wetness impregnation method. The physicochemical characteristics were obtained by advanced instruments. The highest degree of nickel dispersion on Al-SBA-15 was obtained when the Si/Al ratio was 132 and the corresponding smallest average active nickel particle diameter is 38 nm. The adsorption and dispersion of nickel onto Al-SBA-15 was significantly relevant with the ratios of Brønsted acid site to Lewis acid site as well as the ratios of weak acid site to strong acid site. HDO experiments were carried out over Ni/Al-SBA-15 with different Si/Al ratios. 16Ni/S2-R catalyst with high quantity of acid sites and good dispersion of nickel showed high catalytic activity during hydrodeoxygenation of eugenol. A possible reaction mechanism was concluded based on the reaction results.