Carbon Nanofiber Supported Transition-Metal Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

Abstract

Hydrodeoxygenation (HDO) studies over carbon nanofiber-supported (CNF) W2C and Mo2C catalysts were performed on guaiacol, a prototypical substrate to evaluate the potential of a catalyst for valorization of depolymerized lignin streams. Typical reactions were executed at 55 bar hydrogen pressure over a temperature range of 300–375 8C for 4 h in dodecane, using a batch autoclave system. Combined selectivities of up to 87 and 69% to phenol and methylated phenolics were obtained at 375 8C for W2C/CNF and Mo2C/CNF at >99% conversion, respectively. The molybdenum carbide-based catalyst showed a higher activity than W2C/CNF and yielded more completely deoxygenated aromatic products, such as benzene and toluene. Catalyst recycling experiments, performed with and without regeneration of the carbide phase, showed that the Mo2C/ CNF catalyst was stable during reusability experiments. The most promising results were obtained with the Mo2C/CNF catalyst, as it showed a much higher activity and higher selectivity to phenolics compared to W2C/CNF.