Improved Pd/Ru metal supported Graphene oxide nano-catalysts for hydrodeoxygenation (HDO) of Vanillyl alcohol, Vanillin and Lignin
Pd and Ru nanoparticles supported on graphene oxide (GO) [Pd@GO and Ru@GO] and bimetallic [Pd/Ru@GO] were prepared and well characterized by XRD, FT-IR, EDS, TEM, XPS and ICP-AES analysis. The prepared nano-catalysts were tested for hydrodeoxygenation (HDO) of lignin monomer molecules- vanillyl alcohol and vanillin. In comparison to previously reported methods, Ru@GO and bimetallic Pd/Ru@GO catalyst showed high activity and selectivity, under milder conditions, at room temperature and 145 psi H2 pressure, for the formation of p-creosol, a value added product, as a potential future biofuel along with having antibacterial and anti-insecticidal properties. The multifold advantages of both these catalysts are in terms of reduced catalyst loading with lower metal content and ambient temperture conditions resulting in higher conversion of the starting material. Further the efficacy of the developed methodology using Ru@GO and bimetallic Pd/Ru@GO catalyst under the optimized conditions, was tested on the phenolic components of commercial lignin obtained by photo-catalytic fragmentation using TiO2, to obtain a mixture after HDO which contained vanillyl alcohol and p-creosol among others, as indicted by HPLC-MS analysis.