Cobalt-based core@shell catalysts for guaiacol hydro conversion: use of salicylic acid as a sacrificial modulator of the interaction between the metal phase and the silica support

Abstract

In this work, four cobalt-based catalysts were obtained using two routes of preparation which differed in the expected degree of interaction with the silica matrix, using salicylic acid as a sacrificial modifier during the synthesis to modulate the interaction between the cobalt phase and the silica support due to its complexing properties. The catalysts were tested for the hydroconversion of guaiacol at 300 degrees C and 5 MPa of H2, with clear differences between each procedure. It is found that the synthesis route has a deep impact on the catalytic activity, with the catalysts prepared using a one-pot route being less active and having an increased selectivity to cyclohexane. In contrast, the ones prepared using a two-step process have increased yield towards phenol and cyclohexanol under the conditions used herein. Salicylic acid increases the catalytic activity in comparison to the untreated material for both families of materials, without changing the observed selectivity between samples with the same preparation.nSalicylic acid as a cobalt-based catalyst modifier enhances the activity with increased selectivity towards cyclohexanol. This is linked to changes induced by the modifier over the cobalt surface, allowing for tuning of the catalytic activity.