Highly efficient transfer hydrodeoxygenation of vanillin over Sn~(4+)-induced highly dispersed Cu-based catalyst

摘要

Developing highly efficient non-noble-metal catalysts for the upgrade of abundant and low-cost renewable raw biomass into high-quality biofuels and important chemicals is especially desirable, but still remains huge challenges. Herein, Sn4+-induced highly dispersed Cu-based catalyst, Cu/Zn-Al-Sn layered double hydroxide (Cu/ZnAlSn-LDH), is delicately constructed for catalytic transfer hydrodeoxygenation of vanillin to promising 2-methoxy-4-methylphenol (MMP) biofuel using 2-propanol as hydrogen source and solvent without any external hydrogen supply. Nearly total MMP yield is achieved under moderate reaction conditions (180 degrees C, 4 h) and the turnover number (TON) value calculated in Cu/ZnAlSn-LDH is about 3 times higher than that in Sn-free catalyst (Cu/ZnAl-LDH). Characterizations results reveal that the Sn4+ species confined in the lattice of brucite-like layer of ZnAlSn-LDH are existed in electron-rich state, which can promote the formation of smaller Cu nanoparticles (1.95 nm) in Cu/ZnAlSn-LDH compared to those in Sn-free Cu/ZnAl-LDH catalyst (6.08 nm), as well as stronger metal-support interaction, thus leading to the higher catalytic performance and stability. The present findings offer a new avenue to strategically fabricate highly dispersed non-noble metal catalysts with enhanced catalytic performance by adjusting surface structures and compositions of supports for a wide range of hydrodeoxygenation of other biomass-derived compounds without any external hydrogen.