Selective hydrodeoxygenation of lignin phenols to alcohols in the aqueous phase over a hierarchical Nb2O5-supported Ni catalyst†
It is a challenge to promote aqueous-phase precise conversion of renewable lignin to valuable chemical building blocks via engineering transition metal catalysts. Motivated by the water effect in promoting catalytic activity, a Ni/Nb2O5 catalyst assembled from plenty of Nb2O5 nanoplates enabled efficient selective hydrodeoxygenation of lignin-derived phenols to alcohols in the aqueous phase. Taking advantage of hierarchical plate features, the interactions between Ni and Nb2O5 plates were enhanced, with the generation of additional interfacial Ni–NbOx sites. The presence of water significantly enhanced the selective hydrodeoxygenation performance by promoting hydrogenation and hydrolysis, and retarding the dehydration process. Through this strategy, the overall yields of alcohols for lignin oil upgrading reached 73.5 wt% in water at 220 °C.