In situ topologically prepared Co–Zn-based mixed metal oxide bimetallic catalysts for guaiacol hydrodeoxygenation

Abstract

Bio-oil, derived from biomass pyrolysis, can be used as an alternative to fossil fuels after treatment through hydrodeoxygenation (HDO) reactions. In this study, a series of Co–Zn-based mixed metal oxide (Co-Zn-MMO) catalysts were synthesized using Co–Zn-based layered double hydroxide (Co-Zn-LDH) as a precursor. The catalysts were then used in the HDO reaction of guaiacol and larch wood-derived bio-oil. The Co–Zn-MMO catalysts were characterized via scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectroscopy, hydrogen-based temperature-programmed reduction, and ammonia temperature-programmed desorption techniques. Among the Co-Zn-MMO catalysts, the Co1-Zn2-MMO catalyst, with a Co-to-Zn molar ratio of 1:2, exhibited the highest acidity, the largest pore size and pore capacity, and the highest density (65.56%) of Co2+δ-Ov-Zn2-δ oxygen vacancy. These characteristics resulted from the metal–support interaction effect, leading to superior HDO activity for guaiacol. Furthermore, the Co1-Zn2-MMO catalyst effectively removed heteroatomic components from larch wood-derived bio-oil, thereby enhancing the quality of the bio-oil product.