Manipulating the interfacial species on carbon nanospheres supported nanoparticulate Ru to boost the electronic metal-support interaction for enhancing selective hydrogenation of levulinic acid

Interfacial synergistic catalysis of supported metallic catalysts via engineering the electronic metal-support interaction (EMSI), i.e., manipulating the electronic/geometric configuration of interfacial sites, is an efficient strategy to promote their performances in structure-sensitive reactions, such as selective hydrogenation of levulinic acid (SHLA) to gamma-valerolactone (GVL). Herein, carbon nanospheres (CNSs) with controlled morphology and tunable contents of surface carbonaceous species were facilely fabricated to support Ru nanoparticles (NPs). Combined with spectroscopic and microscopy characterizations, the EMSI between Ru and the special C = O species on interface of the Ru/CNSs catalysts was recognized, which contributed to the formation of small-sized Ru NPs with interfacial electron-deficient Ru (Ru delta+) sites. Such modulated electronic configuration of interfacial sites facilitated the H-2 adsorption strength and capacity, eventually lowering the apparent activation energy (E-a) and boosting the intrinsic activity of Ru/CNSs in SHLA. A linearity between the turnover frequencies (TOFs) of levulinic acid (LA) and the contents of C = O species was demonstrated, substantiating the interfacial synergistic catalysis-mediated activity promotion evoked by enhancing the EMSI on Ru/CNSs.