Selective hydrogenation of levulinic acid over a highly dispersed and stable copper particles embedded into the ordered mesoporous carbon supported catalyst

Abstract

Transformation of levulinic acid (LA) to γ -valerolactone (GVL) via hydrogenation is a greener approach in synthesising the eco-friendly GVL fuel additive. In this work, highly active and stable pre-synthesized copper nanoparticles (CuNPs) are embedded and distributed into the ordered mesoporous carbon (OMC) support material by the chelate-assisted multicomponent assembly pathway method. The Cu/OMC nanocatalyst is characterized by different analytical instruments to determine the key properties. The ordered mesoporous carbon (OMC) structure was formed successfully by controlled synthesis steps via resol carbonization. The morphology and structure of OMC was confirmed by the XRD, TEM and HRTEM analysis. The OMC surface was functionalized with different oxygen-containing functional groups, which enhances the interactions with the Cu nanoparticles. The TEM micrographs reveal that Cu NPs with average size of ~5.5 nm was evenly distributed over the surface of the OMC matrix. The synthesized Cu/OMC catalyst showed remarkable activity and stability due to confinement effects of Cu in mesoporous carbon and the highly dispersed nanosized Cu particles, which are exposed sites over the support. More importantly, the stability of the Cu/OMC was excellent, and the activity did not decline even after 60 h time on stream test under optimized conditions (WHSV-2.28 h−1, 20 wt% aqueous LA, H2 flow- 30 mL/min, 260 °C at 0.1 MPa hydrogen pressure).