Highly Efficient\nSelective Hydrodeoxygenation of Guaiacol\nto Cyclohexanol over Co/ZrSi‑<i>x</i> Catalysts

Hydrodeoxygenation\nof guaiacol (GUA) to cyclohexanol\n(CHL) using\nnonnoble-metal catalysts is a valuable area of research. This work\ninvolved the preparation and application of a series of 20Co/ZrSi-<i>x</i> (<i>x</i> = 0.1, 0.2, 1) with various Zr/Si\nmolar ratios for the selective hydrodeoxygenation of GUA to CHL. It\nwas discovered that adding Zr species promotes the dispersion of Co\nand facilitates the reduction of Co species, thereby improving the\nhydrogenation activity of the catalyst. Furthermore, the high electron\ntransfer between Zr and Co increases the content of Co–O–Zr<sup>3+</sup>–Vo sites, which enhances the ability to remove methoxyl\nselectively. More importantly, kinetic studies and <i>in situ</i> diffused reflectance infrared fourier transform spectroscopy (DRIFTS)\nresults show that 20Co/ZrSi-0.2 preferentially adsorbs and activates\nmethyl groups and the reaction is more favorable to the intermediate\nphenol pathway. Under optimized conditions, 20Co/ZrSi-0.2 gives >97.3%\nyield of CHL and exhibits excellent cycling stability.