Reaction pathways for the HDO of guaiacol over supported Pd catalysts: Effect of support type in the deoxygenation of hydroxyl and methoxy groups

•Hydrodeoxygenation of guaiacol at gas phase over supported Pd catalysts.•Phenol and methanol are the main products regardless of the type of support.•Simultaneous adsorption of hydroxyl and methoxy groups from guaiacol molecules.•The hydroxyl group strongly adsorbed onto the catalyst block the active sites.