Search

[Display omitted] • ZIF-8 derived ZnO@NC can anchor Ru nanoparticles to create Ru-O-Zn interface. • Ru/ZnO@NC achieved complete conversion and 99.2% GVL yield in LA hydrogenation. • Ru/ZnO@NC achieved excellent reaction activity with a TOF of 6032 h−1 at 40 °C. • Reaction mechanism of LA hydrogenation to GVL has been revealed by DFT calculation. • Ru-O-Zn interface can remarkably decline activation energy of rate-determining step. Highly efficient synthesis of valuable γ-valerolactone (GVL) by levulinic acid (LA) hydrogenation is of interest for biomass refinery, but it suffers from great challenge to design highly active Ru-based catalyst at low temperature. ZIF-8 derived ZnO@NC nanocomposite can firmly anchor Ru nanoparticles to create strong Ru-ZnO interfacial structure, as revealed by characterization techniques and DFT calculations. By optimizing Ru content and ZnO particle size, Ru/ZnO@NC achieved excellent reaction activity with a turnover frequency (TOF) of 6032 h−1 at low temperature of 40 °C, which is never reported before. After etching the accessible ZnO, the TOF value was significantly declined to 125 h−1 on Ru/ZnO@NC-HF owing to the lack of effective Ru-ZnO interface. DFT calculation results demonstrate that the Ru-ZnO interfacial structure can facilitate the activation of intermediate CH 3 CHOCH 2 CH 2 COOH* and remarkably decline the activation energy barrier of rate-determining step (CH 3 CHOCH 2 CH 2 COOH + H = HPA) from 1.28 eV to 0.82 eV, thus leading to excellent activity of LA hydrogenation at low temperature. [ABSTRACT FROM AUTHOR]

• TiO 2 nanosheets supported Ru nanoparticles form strong interfacial Ru O Ti structure. • Ru/TiO 2 reached the highest TOF of 19,045 h−1for levulinic acid (LA) hydrogenation. • 99.1% yield of γ-valerolactone (GVL) was achieved over Ru/TiO 2. • DFT calculations clearly elucidate reaction mechanism of LA hydrogenation to GVL. • Ru/TiO 2 interface tunes rate-determining step from LA hydrogenation to cyclization. Highly efficient synthesis of valuable γ-valerolactone (GVL) by levulinic acid (LA) hydrogenation is still a challenge for Ru-based catalysts under mild condition. In this work, we have reported that ultrathin TiO 2 nanosheets supported Ru nanoparticles showed extraordinarily high catalytic activity, GVL yield (99.1%) and reusability owing to the formation of Ru O Ti interfacial structure. The turnover frequency (TOF) reached as high as 19,045 h−1 at 100 °C, much higher than those of Ru/SiO 2 , Ru/GO, Ru/MoS 2 , and commercial Ru/C. DFT calculation elucidates that the dominant reaction pathway of LA hydrogenation to GVL is preferentially hydrogenated to CH 3 CHOCH 2 CH 2 COOH*, followed by cyclization to CH 3 (OH)C 4 OH 4 OH* (GVL − OH) and final dehydroxylation, irrespective of surface structure. Compared to Ru (0 0 2) facet, Ru/TiO 2 interfacial structure changes the rate-determining step from initial hydrogenation to cyclization, which greatly declines the activation barrier from 0.81 eV to 0.48 eV. [ABSTRACT FROM AUTHOR]

Owing to their attractive optical and chiroptical properties, chiral metal halide perovskites have received increasing attention, with potential applications ranging from photonics and optoelectronics to spintronics. Metal halide perovskite nanocrystals with either intrinsic or extrinsic (e.g., chiral ligand‐induced) chirality have been reported recently, and the interplay between these two types of chirality has yet to be addressed. Herein, the inversion and tuning of excitonic optical activity is reported in intrinsically chiral perovskite nanoplatelets, originating from interactions between their structural chirality (due to the spontaneously formed screw dislocations in the crystalline lattice) and the surface enantiomeric (R/S) chiral ligands R/S‐phenylethylammonium bromide. Through post‐preparative exposure of the perovskite nanoplatelets to these R/S ligands of varied contents, either chiral ligand‐induced intrinsic chirality inversion or negative and positive Cotton effects induced by the ligands via electronic coupling between the ligand and the nanoplatelets are identified. These findings deepen understanding of the modulation of excitonic optical activity in chiral perovskites and can guide the rational design and synthesis of novel chiral materials. [ABSTRACT FROM AUTHOR]