Rongrong Li

Preparation of carbon nanotubes/BiOBr composites with higher visible light photocatalytic activity

A novel flower-like photocatalyst CNTs/BiOBr was successfully prepared by a facile hydrothermal method. The morphology and the physicochemical properties of the prepared samples were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), and UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity was evaluated by degradation of Rhodamin B (RhB) dye. It was demonstrated that CNTs/BiOBr photocatalyst could effectively photodegrade RhB under visible light (VL) irradiation.

An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes

We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.

Pd supported on N-doped-ordered mesoporous carbons’ catalysts for selective hydrodechlorination of 4-chlorophenol

Pd catalysts supported on N-doped-ordered mesoporous carbons (NOMC) have been prepared and tested for selective hydrogenation of 4-chlorophenol (4-CP) with H2. The difference from the previous methods is that the NOMC was synthesized using urea as nitrogen source via one-pot route. The rate constant of Pd/NOMC for hydrodechlorination of 4-CP was about 135.9xa0h−1 which were higher than Pd/OMC (65.6xa0h−1) and Pd/AC (20.8xa0h−1). It could be attributed to the synergetic effects of mesoporous structure, N-doped supports, and the stabilized small PdNPs. The conversion changed from 100 to 90.2% after the sixth reaction using Pd/NOMC which could be caused by the palladium leaching.

Gold Promotion of MCM-41 Supported Ruthenium Catalysts for Selective Hydrogenation of α,β-Unsaturated Aldehydes and Ketones

In the challenging α,β-unsaturated aldehydes and ketones hydrogenation to unsaturated alcohols (UA), Ru–Au/MCM-41 exhibits superior high activity and selectivity compared with monometallic Ru. TEM and XRD measurements were applied to characterize as-prepared Ru/MCM-41 and Ru–Au/MCM-41 catalysts. The results indicated that the addition of Au significantly improved the dispersion of the metallic Ru components, thus enhancing the activity of the catalyst. The enhancement of selectivity to UA could be attributed to the interaction of Ru and Au components in the support and the morphology effect of Ru, which are revealed by in-suit DRIFTS, H2-TPD, XPS, and FTIR measurements. The morphological and electronic aspects of Ru particles lead to a favorable adsorption of C=O bond versus C=C bond. A dramatic increase in activity and selectivity of the reactions were observed upon the addition of Au, suggesting that the significant synergistic effects between Ru and Au play an important role in the activity and selectivity of the reaction. It is the first time that chemoselective hydrogenation of α,β-unsaturated aldehydes and ketones were studied on Ru–Au/MCM-41 catalysts.Graphical Abstract

A general and mild Cu-catalytic N-arylation of iminodibenzyls and iminostilbenes using unactivated aryl halides

A ligand-free, highly efficient Cu-catalytic N-arylation of iminodibenzyl and iminostilbene derivatives with a broad scope of unactivated aryl halides under mild conditions has been developed for the first time. Moreover, the first Ni-based catalytic system was also applied to the N-arylation of pre-existing derivatives. These novel protocols provide facile and convenient access to the construction of dibenzazepines and offer promising alternatives to the widely used palladium catalysts.