The low-temperature deep hydrogenation of polycyclic aromatic hydrocarbons (PAHs) remains a challenge for producing high-value chemicals or high-density fuels. Herein, Ru/anatase TiO2 (101) catalysts were prepared using an electrostatic adsorption method combined with different reduction treatments (NaBH4, N2H4·H2O, and H2/Ar as reductants). The metal–support interaction (SMI) was tailored, and uniformly dispersed Ru nanoparticles (size <2 nm) were obtained for all catalysts. For the Ru/TiO2 catalyst reduced by NaBH4 (Ru/TiO2–NaBH4), the overencapsulation effect of TiO2–x overlayer induced by SMSI is eliminated using NaBH4 reduction to expose more metal sites. The moderated metal–support interaction favors the generation of more electron-deficient Ru species (Ruδ+). These active Ruδ+ species exhibit excellent ability to promote H2 dissociation and enhance the isomerization rate of saturated aromatic compounds. Due to the enhanced adsorption of aromatic molecules, Ru/TiO2–NaBH4 exhibits superior hydrogenation performance and good stability. Under mild conditions (60 °C, 4 MPa), Ru/TiO2–NaBH4 achieves 87.9% conversion of acenaphthene (Ace) within 1 h and then up to 100% conversion with a 94.4% cis-selectivity of PHA within 3 h, with a high turnover frequency (TOF) of 2797.7 h–1, and the catalyst could be reused three times without significant loss of activity. This study provides new insights into the rational design of highly efficient PAHs deep hydrogenation catalysts under low-temperature conditions.
Tian et al. (2026) studied this question.