Hydrodeoxygenation of lignin-derived phenolics over facile prepared bimetallic RuCoNx/NC

Abstract

Cyclohexanols, promising oxygenated fuel additives and value-added chemicals, can be obtained by hydrodeoxygenation (HDO) of lignin-derived phenolics. Here, an N-doped bimetallic RuCoNx/NC catalyst was facilely prepared for HDO by direct pyrolysis of chitin impregnated with precursors of Ru and Co. Characterization of RuCoNx/NC with N2 sorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and NH3 temperature-programmed desorption (NH3-TPD) reveal that the metallic particles of electron-deficient Ru species and electron-enriched Co species were uniformly anchored on the micro-mesoporous N-doped carbon matrix with high dispersion and nano-scale size. The abundant accessible active sites and continuous spillover of H from Ru to Co make RuCoNx/NC an excellent HDO catalyst. 4-Propylguaiacol, a typical phenolic compound from lignin degradation, was hydrodeoxygenated into 92% 4-propylcyclohexanol over RuCoNx/NC at 210 ℃. With temperature increasing, propylcyclohexane became the major product, possessing 95% selectivity at 280 °C after 6 h. Reusability tests show that RuCoNx/NC can be recycled four times without the loss of conversion and initial selectivity. HDO of other phenolic compounds confirms the general applicability of RuCoNx/NC.