Selective hydrodeoxygenation of lignin model compound to renewable fuel precursors using two-dimensional nanosheet Ni/HZ5-NS catalyst

The catalytic upgrading of renewable lignin to value-added transportation fuels and chemicals is considered as the best solution to environmental and energy-related issues, however, such conversions are challenging. In this study, a new type of two-dimensional (2D) nanosheet catalyst, Ni/HZ5-NS (50 nm), was synthesized and used to catalyze the selective hydrodeoxygenation of a lignin model compound, 4-ethylguaiacol, to prepare renewable fuel precursors (C 8 –C 16 alkanes). The Ni/HZ5-NS catalyzed conversion of 4-ethylguaiacol to ethyl-cycloalkane reached 100%, and the product selectivity was greater than 95%. The microenvironment of the Ni species in Ni/HZ5-NS was regulated by HZ5-NS. The catalytic activity of Ni/HZ5-NS was twice than that of the traditional Ni/HZ5 catalyst. The high catalytic activity of Ni/HZ5-NS can be attributed to the synergy between the electron-rich Ni and the acidic sites on HZ5-NS but more importantly to the 2D nanosheet structure, which reduces the mass transfer resistance of the system and facilitates molecular diffusion. The application of Ni/HZ5-NS to catalyze C–O bond cleavage was extended to other lignin-derived aromatic ring compounds, and the conversion was found to reach 100%. Importantly cycloalkanes could be obtained with high selectivity. Therefore, this study will be useful for extracting alternative sources of valuable fuel precursors from biomass.