Reactive interfacial oxygen vacancies in Ru/TiO2 for efficient reductive amination of bio-based carbonyl compounds

Reductive amination of carbonyl compounds such as biomass-based furfural to valuable primary amines is of great importance. However, it often suffers from low efficiency and moderate amine yield. In this work, Ru-loaded TiO 2 nanosheets (NS) enabled stable and efficient conversion of furfural to furfurylamine (FAN), with 97.0 % yield and very low apparent activation energy (20.3 kJ/mol). XPS, EPR and Raman spectra reveal presence of abundant interfacial oxygen vacancies on Ru/TiO 2 -NS, and the intrinsic activity of various Ru/TiO 2 linearly increased with their oxygen vacancy concentration. DFT calculation confirms that oxygen vacancies induce to generate coordinatively unsaturated Ru species, which enhances activation of key intermediate imine. The activation energy of FCH 2 NH (F, furan group) hydrogenation to FAN has been remarkably decreased from 1.07 eV to 0.82 eV on Ru/TiO 2 -NS. Our results illustrate the potential of utilizing interfacial oxygen vacancy sites in enhancement of reaction performance for biomass amination.